This is driving me crazy. First of all I have an 88 GTA. 5.7 TPI stock. I got the car about 6 months ago and have been working to get it running where I think it should be. My first nagging issue is an off idle hesitation. I checked the archives but am still stumped. Did all the basic tune up stuff as far as plugs, wires, etc. I replaced a bad O2 sensor, adjusted the TPS to .54 and the computer was cleared of codes. Timing is 6 degrees, fuel pressure is 44. This hesitation happens only off the start.It happens if I feather the throttle but is VERY noticable if I go mid/full throttle from a stop. Along with that is a bad shudder/shake in the acceleration at 2000 RPM. This occurs at any speed. It's to the point I hate seeing that 2 coming on the tach. 1800RPM fine....2200 RPM again fine. This is driving me absolutley insane. Please give me some ideas of what else could be causing these probelms! Any responses would be greatly appreciated.

 

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Put a light on each hole at 2k and make sure they are firing

 

Ok, I guess it's time to show off my lack of knowledge in regards to this car. What holes are you referring to in the above post? And what type of light....a timing light or will any light work? I'm sorry if the answers to these questions should be obvious. I am just starting to learn about this engine which makes the problems I am having all the more frustrating because I don't know what steps to take to resolve them. The plugs and wires should be okay due to the fact they are new, but I will check them as well.

 

it was early in the morning ..


Use a inductive pickup timing light on each plug wire one at a time when it experiences this abnormal condition. Thats a good start.

 

How old is the gas?

My car used to shake from 1750-2000rpm, with very old gas in it. I ran it to empty and filled it up with 93 octane. Now it runs fine!

 

My car did this and it ended up being the EGR valve. Try disconnecting the vac line from under the TPI and see how it goes.