Sierra :: 1991 GMC Engine Has Been Stumbling
Oct 6, 2013
I have a 1991 gmc 1/2 ton with 200K on it. Its a 350 engine. The engine has been stumbling for a long time. I've tried many things ...new fuel pump and filter...complete tune up.....checked all vacuum lines..replaced a couple lines...EGR valve.....changed head gasket and intake gasket. Checked the warm up flap inside the air cleaner. I am now very very frustrated.
This stumbling happens often but intermittent also....sometimes worse than other times like the truck is about to stall. The truck seems like its being held back like a loss of power. The truck will begin to stumble so i will pull over and rev it up and it seems to clear itself for a short while then right back to stumbling.
Upon warmup in the morning she seems to run fine until hot. No codes being thrown ...service engine light NOT on. Even while at a stop i will hold the throttle part way and revs at different rpms. I am now at a loss and feel defeated.
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I just purchased a 91 sierra sle with the short bed. I am interested in buying a cap for it because the snap on tonneu cover is falling apart and id like a cap. Would caps from other full size short bed pickups work or does it have to be from a sierra/silverado?
Also i notice the oil pressure fluctuates from around 20 to 80 depending on if I am idle (20) to acceleration at 80, when driving it seems to go up and down to depending on the accelerator position. is this normal??
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This truck has 180km on it and runs fine except as of lately i have developed a surge while at constant speed. When i step on the gas it does not seem to happen.....it only happens when I reach a constant speed. The odd time it will surge at idle and the engine will rev up and down on its own also. When at highway speed it seems to not do this. The truck never dies completely....just surges slightly.
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I'm working on getting my GMC seirra 1500 5.0 L running. Last fall When I was making a trip to another town, it broke down. When it broke down it smelt like plastic was burning, I was unable to figure out what the smell was.
First I though it was a bad battery connection, or that the starter had went.
I changed the Battery, made sure the cables were good. changed the starter and it still doesn't work.
I know the battery is working for sure because There is power to the lights so I can turn on the brights. There is no power to anywhere else on the dash though other then the icon that shows the brights are on.
When I try to turn the engine over, nothing happens at all. Doesn't even make a clicking noise.
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I just bought this nicely used 1991 GMC Sierra 1500 series pickup truck for $650. It started up and ran fine when I gave the seller the money - the few leaks in the break lines.
Easy fix right!
So my son (19 that knows it all) and I went and changed all the brake lines (made everything one size 3/8 line.) Filled it up with break fluid and started the truck. I had my so pumping the breaks and holding them (his first time) I bled the far rear (passenger side) then I had him turn the steering wheel to the right so I could bleed the front driver side.
He turned, and turned and turned until the engine died.
Now the truck only runs when the steering wheel is turned all the way to the right or all the way to the left.
Going to pull the codes to see what the heck is going on....
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I have a stumbling engine when my chevy shifts into over drive. I have new plugs wires dist rotor coil ign module fuel filter air filter. Checked timing with auto advance unplugged and it is not @ TDC but about 4 deg advanced. It is also not consistent in its stumble.
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My 3.5 intrigue seems to stumble while driving it. It feels as it the engine is stumbling or loses power for less than a second and it will do this a few times in a row and will be fine for awhile and then repeat itself.
This can happen while cruising, slow acceleration or at a stop light. I don't really notice it under harder acceleration. When it does happen i do notice that the rpm's drop a very slight bit.
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A friend of mine has had this 2000 Sierra since new. It has just over 100K and never had any cooling issues before. Last week when it was about 10 below zero she drove it home and it overheated and pumped a couple quarts of antifreeze overboard.
She refilled it the next day and it was fine but got it looked at by a local independent mechanic. I had told her that it was likely a sticky thermostat and it ought to be changed out anyways due to its age. The mechanic thought I was wrong and that she had driven it off to quickly in the super cold weather.
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The issue: Check engine light on. Codes pulled, and he's getting O2 sensor codes (aftermarket exhaust has caused that since he bought the car) and 17705 Pressure Drop Between Turbo and Throttle Valve. The car barely accelerates, and you can hear the turbo spooling, and the engine has small surges. I had VCDS going and went for a drive and noticed his N75 Valve duty cycle was stuck at 5.1% no matter what throttle position he was in. So we're going to the wreckers this afternoon and will pull an N75 valve? The DV is stock and appears to be in good condition, but if changing the N75 doesn't work then that's the next spot I'll look.
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About two weeks ago i had a ton of work done to my W100: clutch, freeze plugs, valve seals, body mount bushing, headers, x-pipe dual exhaust. The shop did tell me before i picked it up that it had a lean pop and the carb needs to be rebuilt.
as of now, it idles fine and drive fine when cold, as it starts to warm up it starts to become problematic - it feels like the engine stumbles any time you try to maintain a constant speed (slight throttle engagement), it accelerates fine, but that's about it. You have to drive it in a constant state of accelerate and foot off gas because it does not like you foot on the gas pedal just a little. if you do keep your foot slightly engaged it will stumble and the exhaust will pop - not so much a backfire as there's not at jerking.
-both coolant sensors are new
-spark plugs are FSM spec champion copper 404/rn12yc
-plug wires are a year old (msd cheaper line)
-timing seems fine (around 8-10 BTDC)
-watched at night to try to see if any arcing was happening, none that i could see or hear
-finagled some exhaust restrictors on the exhaust tips out of rubber plumbing couplers and big lag bolt washers to try to recreate the backpressure from the old exhaust, no difference
-went around the vacuum lines with carb cleaner and propane, couldn't find any distinguishable leaks
Fuel filter about a year old- new fuel pump installed while at shop.
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So i have a 2000 ford ranger 2wd 4cyl .190k miles. My issue is the motor has a very rough/shaking idle,abs light on,and check engine light on.it also continues to blow fuses to the tail lights and dash, haha
Ive had it since it was at 40k and has been a great truck,although lately i have really neglected it.ive changed the spark plugs and new wires new timing chain. I would d love to start trouble shooting some of this stuff this weekend if the weather holds up.
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Mileage 192k. Signs...stumbling/rough engine startup for first time of the day and anytime the engine sits for a few minutes before turning on again (battery charging/speed high enough for engine to start, etc).
2010 Prius engine start stumble - YouTube
Started out with no code, then check engine light started coming on. P0301, misfire cylinder #1. Sparkplugs were replaced, and coil pack for #1 switched with known good one. EGR tube also cleaned of carbon.
Stumbling/roughness has been getting worse, about an inch of coolant used per week of driving. No oil in the coolant, and no coolant in the oil (no milkshake or anything like that).
Dirty fuel injectors were suspected, but no improvement after using Techron. Finally, a boroscope was used to inspect the cylinders through the sparkplug holes, and a very slow leak was found in cylinder #1. Since liquid cannot be compressed, during the compression cycle significant misfiring occurs.
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Got an 07 Screw with only 50,000 miles. Yesterday, wife drove it home from work and said it would only do 45mph and didn't sound good. No warning lights were on, she said. I test drove it in the evening and it ran totally fine. Today, she drives it to work and said it ran real rough and "Check Engine" light was on. I picked it up from her work and it idles very rough and slow, and once you hit about 2000 rpm, it runs decent, maybe even normal. Below that, it stumbles and engine doesn't sound right. "Check Engine" light is either ON steady, or flashing. I don't have a code reader, so its likely going to the Ford Dealer Monday. Is there any way to read the code without a reader?
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I have a 2001 GMC Sierra with a starting problem: When you've driven it long enough for the engine to reach about 210 degrees, if you stop the truck it won't start back up until the engine has cooled down to about 200. It only does this when it's over 80 degrees outside, though.
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This engine will not start unless we dump gas into carburetor. Changed the fuel pump, fuel filter and fuel regulator. At the shraeder valve we are getting 20psi. I hear that it only needs to be at 10-12psi to run. What else is controlling fuel to being dumped into the engine!
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I have a 2007 model, new body style Sierra wt, that has a 4.3 v6, it has 62000. miles, and it has been giving me a (enjine hot a/c turned off warning) and will not let the ac work,
This problem is not a true over heating issue and is happening intermittently, even on a cold start it will sometimes give me this error message and when this is happening it will not register the temp on the gauge, but will activate the electric fans.
I am thinking this is a short at some point or a loose connector but where to look.
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We have been having issues with my son's 97 Sierra running rough when it is cold/damp. It feels like the engine is missing.
Today, which is warm and dry, it started running really bad and it was all he could do to limp it home. It seemed like it wanted to idle fine but when he tried to rev it up the tach would start jumping and it seemed like it was missing.
Could this be a bad cap/rotor? The engine has 200,000 miles and we've never changed the cap/rotor. I changed the plugs/wires probably 100,000 miles ago.
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My truck has been having idle surge, low engine power, says stable tracks is off, computer said TPS pedal sensor. I replaced it. Within 3-4 days my truck does the same thing. I turn it off and eventually my truck runs fine with the exception of my engine light is on truck runs good. I put the computer on it again while the truck running bad and it continues to say it is the TPS sensor.
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I have a 1 ton 2000 GMC sierra (old body style 99') 7.4 liter V-8 Gasser with the Allison 1000 tranny, 4x4. the engine will not crank over..
Battery was dead so I charged it, battery was holding 9v, so i hooked up jumper cables to my new car, gauge showed 12v, so I tried to start the truck.. the fuel pump, antilock brake system, and gauges came on.. as well as the "check engine light", "service engine soon", and battery light... I ensured the trans was in park, even tried neutral.. no crank.
I hooked up the mini scanner tool I have, and got no codes.. cleared the ECU/ECM anyways.. no crank.
I also tried swapping out my starter relay with the A/C relay, and pulling fuses to the ECU/ECM for 20 seconds to clear any issues/codes.. no crank
My next option is to clean the battery cables & terminals (or replace the cables), and replace the battery... the battery is only 2 years old.. due for replacement, but I'm kinda broke right now. The battery is one of those stupid side terminal ones with poor connections to begin with.. is there a top post terminal battery I can get to replace this POC? or will the posts hit the hood?
This is a plow truck, single battery setup (at the moment).. and the fisher 8' plow when running the hydraulic pump severly drains the battery.. lights dim severely, been wondering about a higher rated alternator (factory is rated at 120-140amps), larger power cables... etc.. dual battery system...
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So I have a 2004 GMC Sierra 1500 RWD named Beulah and she is quite the beast... She's got over 260,000 miles (given to me by my father after he used it as a work truck, so mostly highway mileage) and a few little kinks and issues. The one at hand today is some lugging/chugging of the engine usually after wet weather. I live near Lake Michigan and we just got dumped on by lake effect snow, but over this weekend it warmed up and we got quite a bit of rain. After this rain, I went to drive my truck and while it starts just fine and idles just fine, for about 10 or so minutes of initial driving, while at speeds anywhere from 0-30 miles an hour or so, Beulah seems to run a little rough. It almost sounds like she's lugging a bit or something's sticking in her engine. After about 10 minutes or so of driving it seems to fade away so my guess is its just some moisture getting into something and eventually evaporating from the heat of the engine. My questions are 1. Is this bad for my truck? 2. Is there a way to prevent this without spending a fortune?
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My Sierra has the 5.7 Vortec engine with 230,000 miles. Ever since I bought the truck at 208k I've been having a random No-Start condition... It can be cold, warm, or not ran for weeks. I've replaced the Fuel pump (just the pump, not the sender too), MAP sensor, ICM, TPS, and Camshaft position sensor. I'm still thinking its a fuel issue. I get 61 PSI at the test port when ignition is on, 55 when cranking, and 54 while running.
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