Re: Shuttering at acceleration

[nhlcrazy]

if you still have this problem, which i doo, i came up with maybe its the O rings on the intake manifold. because mine will runfine if it sits over night but if it cools down for a couple hours and i start it it stutters and stumbles on a load( somtimes on idle) ... soo the block and the intake maniflod are not sealing correctly and maybe sucking air thru a gap created by the engine block being hotter then the intake manifold .... does anyone think this is a logical idea because i am sick of throwing money into this car and my mechanic finally gave up and told me that its my problem now..... i have replaced plugs, iac valve, iat sensor, air filter, ran sea foam thru thinking maybe injectors, and ran multipal diagnostics and not one code has appeard yet soo i dont know what to doo any more

[maxwedge]

This is what year and engine to start with? Has it been scanned during the event, can you or the mechanic pinpoint which cylinder is misfiring, has fuel pressure been checked, has the hose to the press reg been checked for fuel leakage from the regulator. You see where this is going, way too little info for any real constructive help here.

[richtazz]

Max, nhlcrazy e-mailed me, and the car is a 92 with a 3.1 if that helps you. I can't remember in the e-mail if the plug wires were changed, but that would be my next step if not. The 90-94 Vin-T 3.1's didn't have the intake gasket issues the later Vin-M and Vin-J 3100's have, so I suggested checking the EGR valve and it's pipe for carbon also.

[nhlcrazy]

i have the rigth fule presure and new plug/plug wires ... new ignition all the way thro ... u think a maf or pressure regulator because the problem only happens after it is warm and has been cooled for and hour or two. my dad and i brought it to auto zone and it only stuttered bad about 3 times in at stop lights but when it was driving it was barly noticable if it happend at all

[maxwedge]

Originally Posted by nhlcrazy

i have the rigth fule presure and new plug/plug wires ... new ignition all the way thro ... u think a maf or pressure regulator because the problem only happens after it is warm and has been cooled for and hour or two. my dad and i brought it to auto zone and it only stuttered bad about 3 times in at stop lights but when it was driving it was barly noticable if it happend at all

Check the egr for a carboned up pintle or seat as richtazz says. Make sure all the plug wires are on the plugs securely, cheap wires on this engine can cause intermittent misfires as well as a bad coil, there are other possibilites here, but if it has a noticeable miss this is not usually the fuel system. The Maf could cause this but until you get a cel or more consistant symptoms, this would be guess work.

[tblake]

and check the engine temperature. The ECT sensors in these cars a sometimes known to go bad, and lie to the ecm and tell it the engine is cold when in all actuality it isnt. Which might explain why it runs good when cold is because the air/fuel ratio is close to optimal given the conditions. When the motor warms up, less fuel is needed. Keep in mind that there may be two temp sensors on this car, one for the guage and other for the ecm. You could just have it hooked up to a scan tool after driving it for a while and see what the temp is at, if its abnormally low, its safe to say the ECT sensor for the ECM is at fault. How does it start when warm? Hard to start? Smell Gas? Maybe get a puff of black smoke from the exhaust when starting warm?

[nhlcrazy]

i replaced the intake air temp and nothin changed, when i start it its just lik normal maybe it will stutter when hot but goes away in lik 15 seconds after starting. i havnt noticed any black smoke coming out when i start it , but i was driving it to the shop and my mom was behind me and she noticed it had black smoke and smelled really bad lik gas soo it wouldnt suprise me that its running a lil rich. but the coils are brand new and if a coil were to go out wouldnt it run bad all the time? and i have a new icm in it soo i now its not that either. i have the upper intake manifold taken off right now and i noticed a hose goin to the upper intake manifold was cracked and the hose clamp was not even tightend, soo maybe its that idk ill try it today and see if anything gets any better.... reply if you think of any thing new, your help has been much appreciated thanks

[richtazz]

If you installed Bosch plugs or wires, they could be your issue, as they are junk. When it comes to spark plugs and wires, cheap is cheap.

[nhlcrazy]

i think it was the EGR valve u changeded it and about 40 miles later hasnt made the noise or stuttered ... thanks alot guys ur better then my OLD mechanic lol