engine stalling, surging, rough start, PLEASE HELP

[lilanqel94]

ok so i've been coming to this forum for a few issues, and let me make this clear, this isnt my first bonnie. anyway, when the car staarts its rough for a few seconds, surges then the idle drops to normal and no problems. it doesnt happen everyday, but sometimes in traffic the car will stall out but instantly turn on with no problems. other times when im slowing down or stopped it will act like it wants to shut off and the battery voltage will drop a little, surge to 1500 rpm and then go back to normal. i took it to autozone to check the engine it spit out codes p0102, p0107 and p0122.

any advice will help

[nos4blood70]

You have a MAF, MAP, and TPS code. Sounds like your MAF sensor is done. To test, unplug it when the problems are happening. Car should run without it.

[lilanqel94]

thanks i'll be sure to try that.

[lilanqel94]

if it makes any difference, when the problems are happenning, i hear a weird noise that kinda sounds like my other bonnie used to sound when i drove it with no air filter. then when the prob goes away, so does the noise

[lilanqel94]

ok so i unplugged the maf sensor and then the engine really started to act crazy till i plugged it back in. i take it that the sensor is good?? it was acting fine today, started up in less than a second and no high rpm. but of course it started to act up again so i decided to unplug the tps and it went back to normal. i guess that means i need a new throttle position sensor.

[lilanqel94]

ok i was finally able to find the problem. i replaced the iac valve with no success, drove with maf sensor unplugged with no difference, but then i decided to unplug the map sensor and sure enough the car is running with no issues whatsoever. starts up on a dime, doesn't surge or stall, but as soon as i plug it back in all the problems come back. i will be replacing it by the end of this week.

[MKMike]

Glad you found the problem.

Thanks for posting a follow-up.

[1oldman]

ok i was finally able to find the problem. i replaced the iac valve with no success, drove with maf sensor unplugged with no difference, but then i decided to unplug the map sensor and sure enough the car is running with no issues whatsoever. starts up on a dime, doesn't surge or stall, but as soon as i plug it back in all the problems come back. i will be replacing it by the end of this week.

The feed helps all of us. Thank you! - BC

[nos4blood70]

While you're in there, replace the PCV valve, paying attention to how the o-rings are installed. It is a very cheap part, which if gone wrong can mess with your new MAP sensor.

[lilanqel94]

this car is really starting to aggravate me. i replaced both the sensor and the pcv valve, and it's still acting the same!! i would love to replace the maf sensor but i don't have anything that could take it out. (6 point screw with hole in middle). ugh this is my favorite engine but it's really testing my patience!

[lilanqel94]

wow. to make matters worse, i just drove it around right now and now it's idling high with a weird noise coming from the engine! and when i press the gas there's a half second lag before it picks up. when the noise goes away it idles normally but then it comes back. i'm going crazy over this car.

[1oldman]

I'm not an expert by any means, but it sure sounds like you've got a vacuum leak somewhere. - BC
EDIT: I've been thinking about it, you just might have the beginnings of the plenum failing at the EGR tube. I've never dealt with one like that, but just something to consider. The '05 I have had the plenum just beginning to fail. I had the youngest son replace it and the LIM gaskets when I bought the car. - BC

[zuper8]

this car is really starting to aggravate me. i replaced both the sensor and the pcv valve, and it's still acting the same!! i would love to replace the maf sensor but i don't have anything that could take it out. (6 point screw with hole in middle). ugh this is my favorite engine but it's really testing my patience!

When you try to run your car with the MAF unplugged, at first it doesn't want to run, and you have to fuss with it to get it to start and run. After that ritual is over, and the car has "learned" to run without it, you should notice whether your problem is still there or disappeared. If the problem did not disappear after unplugging the MAF, I would not suspect it is bad. Unless you have a spare lying around, the $150 they cost new would be better spent on diagnosis in my opinion... IF the car did not run better with the MAF unplugged.

If you do want to remove it, you need a security torx key set. It has to be a security set for the hole in the middle. Can't be more than $10 at the parts store.

[lilanqel94]

this car is really starting to aggravate me. i replaced both the sensor and the pcv valve, and it's still acting the same!! i would love to replace the maf sensor but i don't have anything that could take it out. (6 point screw with hole in middle). ugh this is my favorite engine but it's really testing my patience!

When you try to run your car with the MAF unplugged, at first it doesn't want to run, and you have to fuss with it to get it to start and run. After that ritual is over, and the car has "learned" to run without it, you should notice whether your problem is still there or disappeared. If the problem did not disappear after unplugging the MAF, I would not suspect it is bad. Unless you have a spare lying around, the $150 they cost new would be better spent on diagnosis in my opinion... IF the car did not run better with the MAF unplugged.

If you do want to remove it, you need a security torx key set. It has to be a security set for the hole in the middle. Can't be more than $10 at the parts store.

when i turn it on with maf unplugged it fusses around like you said and then it'll surge and idle normally. but i was wondering if the o-ring on the pcv valve being loose can cause high idle and that weird noise i'm hearing. everytime i check the o-ring is out of place, and no one sells that piece, nor did it come with new pcv valve.

edit: forgot to mention that it didn't have a spring, like i've seen on other 3800s.

[lilanqel94]

well upon looking at other pictures i put the o-ring in wrong. i'm gonna be using the car later on today so i'll be able to tell if i fixed the high idle and weird noise.

[KM AXer]

Good luck!

Most of us know how frustrating some runability problems can be.

[lilanqel94]

hahaaaaa my dumb self not putting in the o-ring properly was causing the noise and high idle. the car is now starting on a dime, and earlier before i fixed it the CEL wen't off for about 3 minutes but came back on. (the CEL has been on since i bought the car 3 months ago).

[MKMike]

Glad you got it sorted out---and thanks for posting the result.
So now the check engine light stays off, too?

When we post the fixes, it probably helps many more people than we will ever know.

[lilanqel94]

well no the check engine light is still on and i'm still getting hesitation when i start it but there's no noise, high idle, or stalling or surging while driving. once i replace the maf, i'm sure all my problems will be solved once and for all!

[lilanqel94]

well i am happy to report that the CEL is off! i repeat, the check engine light is now off. i can't get any maf cleaner or even another maf because of my budget right now but i took it out, blew hard on it, scraped off some of the built-up carbon with a flathead screwdriver GENTLY and put it back. the car is giving no more problems or codes, and i'm gonna buy some cleaner as soon as i can.

man, it's crazy how a dirty little sensor can cause the biggest problems on a car. to everyone who replied and helped me out YOU GUYS ARE AWESOME!