Pulling the RV the AC will slowly vent to defrost when the engine is under load and then return to normal when back to normal cruising.. Obviously it's a vacuum problem. Where do I start looking or what is usually the root of the problem.
View 2 RepliesWell mine was. Checked all vac lines, 4wd was fine, tested with vac pump tested ok. So first I replaced the canister. Nope, actually happened more often. Pulled the 4wd solenoid that's mounted on the inner fender, rusted and split just above where the vac lines connect. I capped them and now my a/c is perfect, 4wd is out but for now I can live without 4wd.
View 3 RepliesDiagnostic routine. Anytime the vents are on and the engine produces 2k rpm or more it goes to defrost. ....Why and how to remedy?
View 6 RepliesI have a 2003 Ford Focus ZTS with a ZTec 4-cylinder motor, 5-speed manual transmission, @145K miles (one owner). I had the fuel pump replaced in October 2012. For the past couple of months I have had intermittent engine surges when the car is under load, and it is most prevalent when undergoing heavy acceleration or when going uphill. The engine idles smoothly at about 800-1000 rpm. The problem seems most prevalent when I have more than 1/2 tank of fuel in the vehicle.
I have noticed that when the car is in cruise control mode and surges occur the accelerator pedal depresses as if the engine is trying to get more fuel. Spark plugs, Timing belt, tensioner, and water pump were changed approximately 30K miles ago. Alternator replaced @10K miles ago. No visible leaks around the head or valve covers. Vehicle is driven mostly highway miles in low dust environments. Engine light normally doesn't come on, but today the surges were worse than normal and the engine light came on several times over approximately 1 minute interval. Then the surges stopped and the engine light went out and did not come back on.
I have a 2004 f150 lariat crew cab 4x4 with the 5.4 3 valve. It now has 113 000 miles. Since i got it at 85 000 miles its had a hiss when the engine was under load. So like light acceleration or driving into wind. The guy i bought it from said that it had a manifold leak so that's what i figured it was. I got the manifold fixed and it still hisses. There are no check engine lights. It almost feels like my engine lags when it starts hissing. It sounds like its coming from right on the other side of the fire wall. What it could be?
View 3 RepliesMy wife has an 06 Mountaineer with a V8 and we have been having a problem with hesitation when the engine is placed under a load. The problem occurs most often when the transmission is in overdrive and the engine goes under a load such as driving up an incline at cruising speed. The engine begins to shudder much like a misfire but disappears when the trans kicks down a gear. The check engine light will flash momentarily but it never sets a hard code that I can read.
I have AutoEnginuity scan tool but there are never any codes. I've driven the vehicle with the scanner hooked up and there is never a misfire noted. The car has 96000 miles with, presumably, the original plugs. I'm aware of the potential problems with attempting to change these plugs. Where to look? I don't want to "hang parts" such as mass air flow or throttle position sensor. I've been hoping that the problem would progress to the point that a hard code would be set but none has yet.
I have an 2001 Ford Escape V6 3.0, about 130,000 miles. When the engine gets under high load and low RPM, before downshifting, it will shudder (misfire?). Local shop couldn't reproduce it, but they thought it might have to do with slightly cracked vaccume hose, which they gouged me to replace. No improvement. Next they wanted $700 to replace Valve Cover Gaskets. I decided to become a mechanic and learn how to do that one myself. Sure enough, there was a little oil dripping onto one plug. I replaced the gaskets and all 6 spark plugs successfully. Still didn't fix the problem though.
Symptoms will occur reliably when driving at 45-50 MPH with the transmission in overdrive (1500 RPM), and I begin a slight incline. The vehicle will kind of chug forward (feels like sporatic misfires) in overdrive, getting down to 1200 RPM before deciding to downshift. Generally, I can just give a little more gas to force downshift and avoid the nasty-feeling misfires. Some days, however, it is much worse, and will misfire at idle, and make me feel like I have to treat the gas as an on/off switch to keep the engine from dying. (It has never actually died.)
During a really bad day, I got a flashing check engine light. I did not check codes in time - they've all cleared.
I now have an ODB2 reader logging real-time data. All I can do is prove the conditions that cause the symptom: high engine load at low RPM is the recipe. Nothing seems to show a cause... I may just not know what I'm looking at :-/ . I haven't monitored long enough to record a 'bad' day.
I've read about ignition coil issues on this engine, and weather might explain why this is worse some times than others. However, I wouldn't expect that to be load dependant.
Most of the time it feels like the transmission just isn't shifting when it's supposed to, but on the bad days it seems more than transmission related. When stopped at a light in Drive, this can still occur.
My 99 Ranger ac stops blowing when the engine is under a load. It works fine otherwise. What's the fix?
View 2 RepliesJust bought an '03 Excursion v10 with ~150,000 miles on it (Saturday morning). About 3/4 of my 1.5 hr drive home, when I hit my first small mountain, and I put my foot into it, the ABS light came on, and the speedo started bouncing around. Same thing on the second hill/mountain.
Then, after driving it on a couple small trips this weekend, and towing my 2500 lb boat home (20 min drive), it behaved fine (no big hills, etc). However, I decided to hookup my backup camera. During the 60 or so minutes that I had it sitting with dome lights on, etc measuring everything up (also trying to figure out how to fit my tool box in the back).
When I tried to start it when I was finished, it would just crank and crank and crank. Every now and then, it would try to catch, but never would. Left it sit for another 10 minutes and it started just fine. However, once it started, the ABS light came on for a little while, then went out.
At first, I thought "oh no... fuel pump". But then I started thinking about the speedo and the ABS light going whacko on the hills. I'm wondering if it's a low voltage issue? I had the alternator checked out today, and it tested fine at 13.9v. However, I've heard that those tests aren't always accurate.
It has been since the 80's that I have attempted to do any work on a vehicle. How do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents. I have an 2000 F150 with the large engine with about 112,000 miles.
View 11 RepliesI have a '94 Mazda B3000 3.0L V6. The engine finally gave out at 244,000 miles. I had a used motor installed with approx. 110,000 miles on it. I now hear a knocking sound only when the engine is under load (in gear and accelerating). The knocking is not present while revving the engine while in park or neutral. The transmission was rebuilt last year about this time. I have described this problem to several respected mechanics and they don't know what it could be. What could cause this condition?
View 12 Replies1999 4.6 (106K miles) will stumble / miss when at 35-50 mph under a mid throttle load (just before reaching the downshift point). Has been doing this since I bought the truck at 70K miles.
Computer has no codes, engine runs fine under all other circumstances, and gets a decent ~20 MPG on the highway.
Done the standard tune up items (plugs / motocraft) and cleaned MAF, replaced TPS, tranny flush/ filter. Replaced the left O2 sensor 2 months ago, but it dumped a code and was really noticeable when it went out.
I am about ready to dive off and replace the MAF, but at $100 a shot would like other alternatives to try first. I am really convinced the engine is leaning out and misfiring under this load.
I'll try to explain what the truck is doing best I can. I'm not sure if it's the engine or tranny. When you lug the truck on a hill or put a load behind it and lug it the truck jerks like the engine is cutting out or the tranny is jerking, I can't tell which. You can drive it all day long on a flat road or small hills and you can't make it do it. It does it worse going up a hill with a load behind it. You can lug the truck on a steep hill let off the accelerator and mash it back down and it will do it almost every time. I've tried overriding the overdrive and it still does it. If you keep the rpms above 2000 up a hill it won't do it. I've had it checked by a transmission shop and they couldn't make the truck do it. Also it doesn't throw any codes or put the check engine light on when this happens. 2007 F150 supercrew 5.4 auto, with 88,000 miles.
View 12 RepliesMy truck has 57k miles on it. At 1800-2100 RPM it whines under or over it is just fine. it has a new air filter in it as well, still makes the noise, it doesn't matter what gear i am in, it only does this under load. if i free rev it , it will not do it.
View 2 RepliesSaturday I stuck the ex in a snow drift, rocked it back and forth in low range about six or seven times, once i got it out the engine shudders in overdrive. If i lock out OD it still shudders under load, It starts at around 40 mph, if I push it up to 60 and let off the throttle it stops and is smooth until I start to climb a hill. It never did this before It is a 2001 V10 with 143,000 miles, where to start looking ....
View 6 RepliesI have a 2002 Ford F-150 with a 5.4 Triton. 212,xxx miles. I replaced the cops and the plugs about 6 months ago. I was pulling a trailer up hill last week and the engine was under a load doing about 3000rpm. It began to misfire and give me a flashing mil. However, before I went very far the engine began to run fine. It happened 3-4 different times. However, there is no code recorded. I've driven the truck nearly 100 miles with no problems, but I'm going to be pulling that trailer uphill again next week.
View 8 RepliesI recently bought a 2000 f150 4.6 with 105000 on it I notice when I was driving if the engine got under a load it whined. It does it every time and it does it being parked but not as bad. What it could be?
View 2 RepliesTruck blows smoke like a blown NASCAR engine occasionally when pulling heavy load....pull over, cool off and resume driving. Its as if it never happened. All fluid levels are in range and truck drives fine minus load. My last f350 5.4 did same thing at about 200k miles. My local ford dealer tells me I'm the only guy on earth this Has happened to.
View 8 RepliesWhen I turn on the defrost in my 02 santa fe, the engine smokes. when i'm parked and turn on the defrost, the car stalls out.
What I think is the timing belt seems to be making a funny noise, and my wife thinks she saw the smoke coming from there. it looks to be in good shape, though.
I've had this noise on my 92 GT since I bought the car and it hasn't got any worse but I still am wondering what it is in case it's something serious. I hear a rattle/clatter coming from the engine or thereabouts, and it only happens under load (doesn't have to be heavy load, but I can't hear it in neutral or when the clutch is disengaged). It only happens above around 3000 rpm and the frequency of the rattle corresponds to the engine rpm. It's difficult to pinpoint the location of it because it only happens under load. Anyway, I made a short video of it and uploaded it to YouTube....
View 8 RepliesThe A/C system switches from vent to defrost mode under engine load (going uphill or overtaking another car). It is caused by a vacuum leak and as far as I've seen most of us had the same problem a loose red hose, here are some pictures of where to start looking first.
This is the hose that gets disconnected from the back passenger side of the intake manifold.
This is where that hose should be connected to.
This is the other end of the same hose, it has a check valve on it and this side is connected to the vacuum reservoir and into the firewall to the dashboard to control the A/C system.
This image is just to show the location of the vacuum reservoir, you'll have to remove the cowl in order to see it properly, if you don't you can still reach the reservoir but it will be a bit hard since you don't have much space.
Here's the vacuum reservoir and the hoses from another perspective.