hesitation on acceleration, stuttering noise

[april15_]

My 94 Grand Am hesitates for a second when I accelerate from a stop. It doesn't happen all the time, but enough that I am afraid to pull out into traffic. I'll step harder on the gas when it happens and then it suddenly moves. Also, I'm hearing and feeling a stuttering while the car is idling. It happens in all gears and it also happens occasionally on the highway at high speeds. It sounds kind of like a palpitation. Took the car to the mechanic and he replaced the spark plugs, but the problems are still happening. Can anyone guess what might be the problem? Thanks to anyone who can help.

[gebster76]

I would have the catalytic converter checked out. Sometimes it can get clogged or damaged and some people think it's a tranny problems and spend huge amounts of money and then come to find out it was the cat all along.

[Slade901]

I would go ahead and clean the gunk off the IAC and test the IAC (Idle Air Control solenoid) and if not then replace the IAC.

[matt919]

Clean your Mass Airflow Sensor.

had the same problem here.

[charleshenryjr]

mine too, i just got it, so i figured i was just in third. now i know different by reading all these, engine posts. my engine just went out. fried. soon after repairing and heavy use of the a/c, pontiac dealer says $440 to get car running to perform a diagnostic, also quoted $5k for new delco engine, didn't research rebuild or used install.

[charleshenryjr]

mine too, i just got it, so i figured i was just in third. now i know different by reading all these, engine posts. my engine just went out. fried. soon after repairing and heavy use of the a/c, pontiac dealer says $440 to get car running to perform a diagnostic, also quoted $5k for new delco engine, didn't research rebuild or used install.
p.s. also 94 ga, se, quad, sohc

[Tom94gaGT]

i'm having the same problem...where are the IAC and MAF located, and what should be used for cleaning? just gumout carb & choke cleaner?? and Slade, what would a new IAC cost?

[Markgase2000]

isopropyl alchohol works great

[april15_]

After all this time I'm still having this problem, only it is now getting worse. The car idles making this palpitation sound almost constantly now instead of intermittently, and it sounds like it will stall but it never stalls. The hesitation is definitely occurring at the same time as the stutter(palpitation) sound. Mechanic says he's checked the cat and it''s fine. Mechanic thinks it's an electrical problem and to take it to dealer. I don't have money to spend on diagnostics. Some people here suggested cleaning the IAC or mass airflow sensor. How can I do this and where are these parts located? If anyone has any other suggestions on what the problem could be, please post! Thank you.

[april15_]

One more thing I noticed is the car runs fine while driving, but going up any hills will always make the palpitation sound.

[bdhiggins20]

when they changed the plugs did they change the plug wires? sounds like plug wires to me...

[april15_]

Finally got this problem fixed after 6 frustrating months! Just in case anyone else has this problem...it was the coil cover. The car doesn't have spark plug wires but this instead?

[Slade901]

Yeah, it's called Ignition Coil Housing. It's good to know that a malfunctioning Ignition Coil Housing causes that problem. On our vehicle, I've narrowed down the problem to the Ignition Coil Housing because I've only two sparks out of four.