Grand Prix :: 98 GT 3800 Bad Mileage - No Codes Or Lights
Jun 9, 2008
My grand prix is getting terrible mileage but runs great. Where should I begin checking. There is no codes or lights. It runs good but only gets 18-19 mpg on the hwy. I traded my wifes 97 Bonneville for this car and that big old bonnie got about 26 on the hwy with the same engine. I just assumed the gp would do at the very least the same. What do you guys get with the 98's? I don't know where to start but if it don't get better than that, I'm trading it back for a Bonneville. It has 113k on it. I have put a new Air Filter in it and Thermostat. It seems like it does not heat up very much but I guess it is ok. I put the new Thermostat in and it heats up the same. About 1/4 way up the gauge. I guess like 160-170?
View 14 Replies
Advertisement
I have a 2000 grand prix gtp, I am trying to pull the motor so i can change some things up so i can race it. But how to pull the motor or transmission with it.
View 7 Replies
This has happened to me twice now, 2 weeks between occurrences:
Driving to work, about 10 minutes into the trip - traction control light comes on, "Reduced engine power" message appears on DIC, and check engine light comes on.
The car is an '08 Prix, no charger, with 51K on it. This is actually the first trouble I've had with the car since it left the dealer lot.
I pull over, turn car off. Turn back on - traction light goes out, and engine is running at full power. The check engine light remains on for about 5 starts/stops then goes away.
I haven't had the engine scanned yet. The only thread here I could find recommended replacing the throttle body. The person decided to clean the throttle body, and that was the last post.
I was thinking of removing the individual electronic components from the TB and cleaning them and the area around them in the TB. (I have the sensor-safe cleaner for TB's).
I don't think this error condition would be a warranty issue, but I'm not sure. It's a MAJOR hassle for me to get the car to the dealer.
View 14 Replies
I bought a gorgeous red 4.0L V-6 Mustang very cheap last week because it needed a clutch. I would not even pull the car. Little did I know that the clutch kit, including the slave cylinder and flywheel, was over $600. (But that's another story.)
The car runs now, but will not go over 3800 RPM in any gear. It had NINE codes, which they cleared. I was told that they primarily pointed to the MAF sensor. I cleaned it with the recommended aerosol. I have driven it 20 miles, and the MIL has not returned, but the little wrench symbol has. The Manual says to take it to the dealer (of course). The car seems to run fairly well, with the exception of the low rev limit. It is a "fly by wire" set up, with electronic throttle.
The cleared codes were P0102, P0113, P0135, P0141, P0155, P0161, P0403, P0443, and P0446. They actually repeated on Autozone's scanner. (My six year old Actron won't link to this car for some reason.
View 18 Replies
I just bought a new 2001 Grand Prix. I am not completely car savvy, but I know a few things for a lady.
The battery won't hold a charge.
and the computer diagnostic tester thing says the Headlamp Relay is malfunctioning.
View 2 Replies
I have a 95 Grand Prix 3.1L and I can't turn my key. You can put it in and take it out, but it won't turn whatsoever. It's stuck in my driveway and I've tried just about everything to get it to turn.
View 1 Replies
I'm pulling the engine to overhaul. I've borrowed a hoist and think I'm ready to lift the engine out, but I don't know how to strap the engine to the hoist. I first thought of using the brackets with the eyelets bolted to each head and bought chain and hooks. But I had to remove the rear bracket so I could remove the rear exhaust manifold so I could remove that darn rear engine-transaxle bolt. (That really bites because I want to have the exhaust manifolds on when dropping it back in.)
Are those brackets intended for lifting the engine? If so, I could reinstall the back bracket and give it a go.
Searched the internet for info but didn't find much. Did find a 3800 being lifted with two straps completely under the engine.
Also, the engine-transaxle joint hasn't cracked open yet. I'm guessing it's because they're stuck after 198k miles and will eventually separate. But I did not find one of the engine-transaxle bolts mentioned in the 98 FSM: front lower (#1). I don't see how I could have missed it ; maybe the 99 doesn't have it?
View 4 Replies
Thought my transmission was slipping. So I changed the tanny. been driving it for a few days and now it doing the same thing. Is it possible that it a different problem with the same symptoms?
View 4 Replies
When I turn the car off the key only goes to acc. If I wait a few minutes I can hear a clicking sound coming from the steering column I think. Then I can turn it off all the way.Whats causing this? and how do i fix it. My car is a pontiac Grand Prix 2002.
View 2 Replies
I have a 2000 Grand Prix with a 3.8L engine that will not start. When I turn the key to the run position, the headlights and the dash lights come on, but when I turn the key to the start position, the lights go dim and nothing happens. No sound from the starter. I checked the battery and the starter and they are good. I installed a new positive battery cable. Still works the same. Not sure what else to check.
View 13 Replies
When you are accelerating anywhere from half to full throttle it may cut out at any given time. The RPM will drop down, it may bounce up and down for a bit and recover, or it will drop all the way down and stall. If you let off the gas it may or may not recover. If it stalls so far from the tests I have done if you never shut the key off it will never restart again. If you shut the key off and wait from 5 to 10 minutes it will all of a sudden restart normally like nothing ever happened. If you try to restart it immediately even if you shut the key off and back on it will not start.
When it does not start when I am attempting to start: Fuel pressure according to my gauge is between 55 and 60 psi. Inline spark tester shows that it is getting a spark. Engine sounds normal while cranking so in other words compression sounds normal. I have an LED test light rigged up showing when an injector fires, and it does show electrical activity going to the injector when it opens (flashes). Only clue is that it SEEMS dimmer when it wont start, but I have no clue if thats how it normally is on start up. Its only a slight difference from the brightness of a normal idle brightness. I have a snap on scanner hooked up, nothing that I know of looks abnormal in the data and it will not throw codes when this happens.
Parts I have changed or cleaned so far: Changed the fuel filter, crank sensor, cam sensor, ignition module, and MAF sensor. Cleaned the throttle body. When the car is working normally it runs strong, good power, smooth. Starts great normally.
View 8 Replies
What may be causing my car to harshly shift fron 1st to 2nd and then from 2nd the 3rd. One solution some one had was to replace the:
"TPS (throttle position sensor). The other reason for hard shift is a worn Boost valve and will need to be replaced, or a faulty transmission fluid EPC (electronic pressures control valve). Both Boost valve and EPC are located in the Valve Body and can be replaced with out dropping the valve body, but have to drop the transmission pan".
I did just recently top off the tranny fluid because it was running a bit low but there is no leak....
View 7 Replies
Last year my a/c worked off and on. so far now its not working at all. Compressor isn't kicking on. i bought a bottle of the EZchill refrigerant to recharge the system. I took the relay out and added 12+ to the pin to kick on the compressor. Even with the compressor running the gauges are in the blue range which is the normal operating range. With the compressor running, the air is cold but when i stick the relay back in the compressor wont kick back on. I tested the relay and its fine. Also the compressor is rattling.
View 8 Replies
Last weekend, I saw fluid under the right side of the car when in a parking lot and found a rather large puddle of almost clear, oily fluid on the garage floor when I got home. I figured it was power steering fluid. I just finished a rebuild a couple months ago but the old power steering pump wasn't changed, so I was guessing a leaky hose or seal.
I quit driving the vehicle. A much smaller puddle, barely more than a spot, appeared. But it was much nearer the front of the vehicle than the PS pump. And the PS pump fluid level is still full.
Not much evidence of dripping fluid in the engine compartment. Is it possible that the new motor mount installed just a few months ago cracked and leaked its fluid already? Don't know how I could verify that without removing the mount. I'm at a loss for the source of the fluid.
View 2 Replies
Driving last night and my 08 died after searching I found the ICM fuse was blown. I replaced the fuse and now it has a misfire on cylinder 6. I have changed the coil with no luck. I replaced the plugs and wires about 2 weeks ago and I don't find any problem with the plug or wire. I checked at the coil and there is no spark at all on cylinder 6. I was thinking the ICM is bad but was wanting some opinions.
View 11 Replies
I have an 2002 GT with a 3.8 in it. Two wires broke on my harness that plugs into the shift solenoid so it will not shift out of park.
I got a new harness and wired it how it was wired before but it is not working when I plug it back in. Is there a way to test the new harness to make sure it works?
View 6 Replies
I have a 2000 GP GTP. I went over a speed bump to fast one day, and parked my car. When I got back into the car the next morning, I tried to put my car into drive and it wouldn't accelerate or move. So I put it into lower gear, 1st to be specific, and the car moved normally. I drove like that for a few days with no problem. Then days later I did the same thing, went over a speed bump to fast and now the vehicle wont move at all unless I put it in reverse.
View 2 Replies
I have 02 GT 3.8L with 130k on it. When I accelerate it shakes extremely bad and when I let off the gas it stops. Is that a broken or worn CV joint or something else. And if it is should I replace both sides?
View 2 Replies
After driving to the store, I parked for like an hour. i came back outside to start it and it just clicks. i bought an starter from autozone, it didn't work. I took that one back and got one from advanced auto, it didn't work either. Again it justs make a hard click when I attempt to start.
View 2 Replies
I have a 1998 grand prix the key left in the ignition buzzer keeps going off after I have taken the key out of the ignition and open the door to get out. Everything with the ignition works fine except for it telling me I have left the key in the ignition when I haven't.
View 4 Replies
I just replaced the passenger wheel hub assembly (and axle due to complications) and the noise is still there. I have a loud hum that starts at about 30mph, is present when going straight, but gets much louder as the steering wheel is turned to the left. It is completely gone when turning to the right. It gets louder with speed and how much the wheel is turned left. At highway speeds, on a long sweeping left-hand curving connector, the noise is VERY LOUD. There is a slight vibration that occurs, but it's not bad at all. The noise continues when the trans is in neutral. I've even shut off the car while testing this in a parking lot, and the noise continues. The noise varies depending on the height or load of the suspension. It varies as the car rides over dips in the road.
I really though it would end up being the passenger wheel hub, even though there was no noticeable play in either hub. I've had noisy hubs before that had no noticeable play. But after a very obnoxious repair, it's not the hub. All tie rods have no play. All 4 heels were recently aligned. The alignment made no difference in the noise. I replaced a bad tranny mount about a year ago. Motor mounts look good. Ball joints are good. Replaced axles about 3 years ago. Replaced bad struts and strut mounts about a year ago. New control arms due to bad bushings. All these things I've replaced recently were making noises too, but the left-hand hum is always present. This is my last noise and it's driving me crazy. I've always felt it comes more from the driver's side, but my wife disagrees and my hearing isn't great due to too much range time.
Oh, I recently noticed that the steering wheel tends to want to return to center from the right more than it does from the left. Again, alignment was done by a reputable garage just a few months ago. They also found nothing during there safety inspection. I also noticed that the car is not sitting level as it seems that the rear driver-side spring is sagging about 1.5". The noise is not very obvious from outside the car. I know I'm forgetting some other things I've checked for this problem. I'll post more as I think of it.
My current theories are driver's-side hub, something with the steering rack, spring heights, something vibrating (body panel, loose part?), something with the auto-tranny.
View 5 Replies
