1997 old 88 hessitation while driving.

[blazerk5drew]

Guys I need help.

The olds has been running like a champ since ive rebuilt the engine, but lately, since the harsh cold set in, it has had a hessitation under normal driving. WOT is fine.

List of things I have done

New:
-02 sensors
-ignition module
-plugs/wires
-coils
-motorvac fuel injection cleaning performed.
-fuel pressure checked and it holds
-fuel filter replaced
-MAF
-TPS
-fuel pres. reg.

Engine specs are below. Im wondering if the intense pcm is not working correctly.

One person mentioned water in the fuel tank might cause these symptoms...It does not feel like a misfire at all but rather like it isnt getting fuel (which i believe it to be). I pulled the fuel rail off and cranked the car....all injectors fire evenly and close...although im not sure how they act while driving.

ANY IDEAS??? the car is for sale but id like to have this fixed, otherwise the price might have to come down substantially.

[Jrs3800]

What was the fuel pressure?

[blazerk5drew]

IIRC the fuel pressure was 45 psi at idle and easily went over 50 when throttled. It does have a newer fuel pump...not that that means anything.

[blazerk5drew]

I went and drove the car yesterday because of the warmer weather to see if anything changed and it still bogs way down. I tried shaking wiring to the maf sensor and i checked the engine over again. Im wondering if i need to run a stock pcm to identify codes correctly.

[Tuffguy610]

Is the computer throwing any codes? I know you said you replaced the fuel pump, but I had the same symptoms on a car I previously owned (88' 6000) where the car would sputter on anything but full throttle. I sold the car like that and then ran into the guy a month later and he said the fuel pump blew up right after I sold it . Maybe you have a defective fuel pump. Reading your thread again it also seems that the MAF could be bad. They usually fail without throwing a code. You can't really shake the MAF on these cars since they are embedded into the TB. I feel your pain as I have also 97 Eighty-Eight with a rebuilt engine and it always gives me some type of problem. Good luck.

[blazerk5drew]

The computer throws no codes. the computer has been altered to not show some codes like egr, rear 02 and missfire. im going to try and swap in an oem computer if the fuel pump checks out. This car did sit for a long time before i bought it. Im hoping the fuel pump sock is plugged up and causing fuel volume problems. Ill get back to you guys. I Just bought a new car though so the olds has been on placed on the back burner.

[LeSabre in Buffalo]

What's your KR (knock retard) like?

Mine hesitates (/ed) a lot on light throttle application from a stop/slow sped. Turned out it was the alternator and power steering pump causing lots of false knock, as near as I can figure out. The engine quickly went from idle to about 1600-1700 RPM's, and the change caused the accessories to make more noise that got picked up by the knock sensors as knock, again as what I think was happening. Then the engine pulls timing as a protective measure, which feels like hesitation.