Now my car thinks its a Toyota....

[TheEdgeofSanity]

for the last 3 months, my car has been in and out of the repair shop so much, i am beginning to feel like I don't even own a car anymore!

so, my SES light is chronically on...I have an EVAP leak and the mechanic replaced everything from the gas tank all the way to the engine. he's tested every solenoid, replaced all lines, etc. He tested my car for emissions and I am meeting the requirements of the system so he has no idea. he said that it may have to do with a vacuum sensor located inside the gas tank?

secondly, my car died about 3 weeks ago where it would run, then get bad, then cut out, let it sit for 20 minutes, fire back up and run another 10 miles or so then repeat. I thought fuel pump, so did mechanic. So, he checks fuel pressure, finds out it is low, checks fuel filter and its 100% clogged. Mechanic replaces filter then says that fuel pressure is fine. He test drove it and everything is cool. He says that the clogged filter was overworking the fuel pump causing it to overheat and shut off.

Now, I pick up the car from the mechanic and everything is good until I get it home and start it about 3 hours later to go to my grandma's. The car idles at 3,000 rpms and the accelerator is not stuck. When I put it in reverse, I literally burned rubber because I was not thinking and was not pushing the brake hard. Then driving, I realized that after getting in overdrive, my car could accelerate without me touching the accelerator all the way to 55 mph and maintain it! So, at the next traffic light, I had to hit the brakes really hard to get it to stop and I shifted it to neutral and it revved all the way to 4K before settling down to 2K rpm's before I had to accelerate again for the green light. So, next morning (saturday) it is back at the mechanic. He is super apologetic and decides to look at it while I am there. He suspects it is the TPS going haywire, but had to keep the car until he has more time to diagnose it.

Overall, I go from a car that won't run to a car that is freaking toyota insane! I don't think the mechanic is purposely effing me over, but I am starting to get annoyed that it usually leaves with a new problem once one problem is addressed (and not even fixed!). We have been using this mechanic for years with nothing but good service so I dunno why suddenly things are so bad. He claims that he sees alot of late-GM models with issues like mine.....

[Gr1m]

the new problem sounds like unmetered air is getting into the engine

[Ryan from Ohio]

Maybe a frayed throttle cable hanging up?

[zzyzzx]

How many miles are on the car?

My Escort did the really high idle thing for a couple of days. I was unable to accurately test the Idle Speed control, so I tested everything that gives an input to the computer that would affect the idle speed control. Once I found out that all the inputs were good, I replaced the idle speec control and the problem went away. Now I don't trust idle speed comtrols past 150K miles, espically since you can't clean them particularly good on a lot of cars.

[TheEdgeofSanity]

Originally Posted by Gr1m

the new problem sounds like unmetered air is getting into the engine

you know, I do recall hearing something that sounded like a vacuum leak... maybe I will call him and remind him of that!

[TheEdgeofSanity]

Originally Posted by zzyzzx

How many miles are on the car?

My Escort did the really high idle thing for a couple of days. I was unable to accurately test the Idle Speed control, so I tested everything that gives an input to the computer that would affect the idle speed control. Once I found out that all the inputs were good, I replaced the idle speec control and the problem went away. Now I don't trust idle speed comtrols past 150K miles, espically since you can't clean them particularly good on a lot of cars.

130,400 miles. I don't think thats an extreme amount of miles for my car to be acting this badly!

[comanche]

EVAP leak.... large or small?
EVAP systems are usually quite simple if you have the right equipment... does your mechanic have a decent shop/scan tool/smoke machine?

Beware that when your fuel pump was clogged that it probably put some serious wear on your pump. You may end up stranded. I'd highly recommend that you have your mechanic do a scope test of your fuel pump.

TPS.... usually easy to tell if you can scope test it.
Could also be a large intake leak of some sort, easy to tell with carb cleaner.
Saturns have a problem where you when you set the cruise, the car just accelerates. Crazy!

[TheEdgeofSanity]

Originally Posted by comanche

EVAP leak.... large or small?
EVAP systems are usually quite simple if you have the right equipment... does your mechanic have a decent shop/scan tool/smoke machine?

Beware that when your fuel pump was clogged that it probably put some serious wear on your pump. You may end up stranded. I'd highly recommend that you have your mechanic do a scope test of your fuel pump.

TPS.... usually easy to tell if you can scope test it.
Could also be a large intake leak of some sort, easy to tell with carb cleaner.
Saturns have a problem where you when you set the cruise, the car just accelerates. Crazy!

according to my mechanic he cannot find any evidence of an evap leak. he does have a smoke machine and has done 4 tests on it, finding leaks so small he doubted they could affect anything, yet he repaired them to no avail.

secondly, i asked the same thing about the wear on the pump because of the clogged filter and he said that unless I want to pay the $325 for a pump right now, he wouldn't worry about it until I notice issues and to not let my fuel get below a 1/4 of a tank.

thirdly, I hope he does a live scan of my car to see if the TPS is actually messing up. i intend to request that he does.

[zzyzzx]

For your Alero to more closely approximate a Toyota, it would have to be a newer car with problems. I'm guessing that your Alero has considerable miles on it.

[comanche]

evap leak sounds like a tough one. Depending on where he's smoking it from, could be issues where he's scoping it.
A good idea would be to look up someone who has a subscription to online troubleshooting... I can't think of the name, but there are at least 2 resources that list uncommon problems encountered by technicians, and their final solutions. Basically you enter in your symptoms, and you can see if any technician has ever had that problem.
Ya, you can wait until your fuel pump quits.
Could be TPS, could be IAC, could be a few other things maybe... idk...
It would be good to use an actual scope, not just a scan tool scope...

[zzyzzx]

I'm inclined to think that you do not have the best mechanic for this type of problem. Not necessarily saying that you mechanic sucks, just thet they might be in over their head. You may just need a smarter person to look at your car.

I don't test TPS's with a scanner. I test them with a spare wiring harness piece and a multimeter set on ohms, since a TPS is really just a variable resistor.

[Raziel]

Did your mechanic check the vacumm lines to the MAF sensor or at the throttle body. If there is a vacumm leak it could be simulating an open throttle, and could be the reason for the over rev at idle??, just a thought though

Raz