hesitation when i first start her up

1. the past few weeks she hasnt been doin well. when i first start her up, normally i just pull out right away with no issues (no warm up time like a 4 banger). but l8ly when i start her up and go to pull out. she hesitates pretty bad. i aggressively tap the gas and theres a good sec. between pedal then go. i can tap the gas and let off b4 she responds. i throw her in neutral and rev a few and the problems seems to go away. the problem is getting worse tho. the other day she started to have small back fires, when i tap the gas and she hesitates then small backfire. now today when i was leaving work around 11:30pm. i started her up and the idle was pulsing. up to 1500 then down to 800 and bak and forth and there was some smoke coming out the exhaust. i rev. but nothing helped. i let her warm up for a few and the problem was gone. i put her in drive and pulled a few feet and i heard a clunk. sounded like something fell off the top of my car kinda sound but nothing. its alot to throw out there at once. but really need yalls advice.


2. there has been the steady sound of pulleys goin bad. so next paycheck i will be changing idler and tensioner. but i dont think that has anything to do with it.

3. how often shud i be changing my head gaskets btw? i just hit 115k.

When you do get it going are your shift points okay? I'm thinking TPS, this exact symptom happened to my old '94 Regal and it was TPS. Shift points were wonky and shifts were harsh.

Changing head gaskets is not a 'maintenance' job, there is no reason to replace unless you have a problem.

Yep, sounds like TPS -- you might also do well to look at the throttle body and air mass meter too. A dirty throttle body does things that cause the engine computer to make the idle "hunt." It should be steady. If the throttle body is dirty best thing to do is remove it and clean it. GM service techs know how to do this if you don't want to. You will need torx drivers with the dimple in the end, for removing tamper resistant torx fittings. Once the TB is off you can clean it carefully with TB cleaner. Don't run the cleaner into the ground, use a bucket. And you really should not clean the TB while on the car, if only because that just allows the crud to pass 'downstream.'

As for the air mass meter, make sure the screen is intact, and look at the wire but don't touch. You can't really clean an air mass meter although some people will tell you use a no-residue cleaner such as VOC-type brake parts cleaner. If your AMM is dirty, you need to find the air leak(s) that are letting dirty air past the air filter, and fix them, or go back to a factory air filter setup (maybe you live in a dusty area). A dirty/failing AMM will make your idle hunt. If it is dirty that means you are getting crud on it faster than it can burn itself clean. Most likely you will have to both fix the dirty air problem and replace the AMM.

As for the heads and gaskets, GM engineers decreased the total cost of 3800 engine ownership (for a weight trade off) by using cast iron heads and block. You just don't have the drama with these engines that you do with engines that have aluminum blocks or iron blocks with aluminum heads. Most likely you will get to the point where you ned to/want to rebuild engine before you spring a head gasket leak. Search on this site, however, for info about the LIM gaskets.

Albertj

shifts points are just fine. no issues once it warms up. just a few revs the problem goes away. im thinking dirty tb as well. sounds like a vac leak under the tb area. could just be tb sucking sound. i will check it out and clean tb tuesday when i have time and get back to yall.

thanx

95ParkAveUltra wrote:

no issues once it warms up. just a few revs the problem goes away.

Temperature sending unit? Does it have more than one, one for the gauge and one for the computer?

i believe it has two. i think its just a dirty sensor. i will kno more tues. when i take a look. when it first started happening a few weeks ago. i figured maybe just dirty air filter. so i swapped with a extra clean one i had. it was fine. now its only been like two weeks and its happening again. so it cant be the filter. can it get clogged that fast? next time the car is cold i will be removing the filter and see if it still hesitates.

shift points are fine. car runs great once i rev it or it warms up.

air filter won't affect cold start or any low RPM action. A dirty air filter will only cause a restriction at heavy throttle/high airflow conditions. But the air filter housing does contain the IAT sensor - (Intake Air Temperature), maybe the wires to the IAT are being pulled too tight, causing a break?

deekster_caddy wrote:

When you do get it going are your shift points okay? I'm thinking TPS, this exact symptom happened to my old '94 Regal and it was TPS. Shift points were wonky and shifts were harsh.

Changing head gaskets is not a 'maintenance' job, there is no reason to replace unless you have a problem.

Were those harsh shifts intermittent? Also, did it ever affect how smooth the car started up?

I asked because I've had harsh shifts a few times until I restarted the car, and from time to time it starts but I need to blip the throttle. Never hesitates under accel though.

Forgot to mention, if you pull the TB be sure to use a new gasket for the reinstall...

Albertj

Also, when you pull that air filter do you inspect it (hold it up to the light) to see if it is dirty (clean = can see light thru the peaks and the valleys)?

Albertj