I just bought this '94 Z28 about 4 weeks ago, since I bought it I've had to replace the Distributor, MAP Sensor, Battery, Fuel Filter, Air Filter, Spark plugs, Oil Change, Muffler (put on a 80series Flowmaster) other than all this the car is stock.

Basicly the problem I've had from the start is the car when you romp on it just sputters like it's choking then it'll go a little bit then sputters and etc. really never gets up and goes correctly. But last weekend I reset the PCM (computer) by just pulling the PCM fuse & removing the Neg. from the battery and all week the car ran just fine, if I'd romp on it, it seemed like it had a sec or so lag to it but it would break the tires loose and go.

Just last night I took it to Thunder Valley (noble, ok) and ran it there only three times the first time I ran it, I kept it in (D) (yes automatic) and the car other than spinning the tires alot didn't do very good at all. Which also I've noticed that the rev' limiter might be moved. the next 2 runs I made I started in (1) and at about 4.5k - 5k rpm -> (2) 4.5k - 5k rpm -> (D). This seem to work alot better, but the problem came back again. in the second run when I went from (2) to (D) about a sec or so into (D) around 80mph the car started sputting and acted like it was trying to downshift and the check engine light came on. I ran it again just to see if it would do it again and it ran fine until I put it in (D) then sputtered. So I quit and when home. later that night went to get pizza, and my check engine light was off, but the whole time in (D) the car just sputtered and after about 30mins of driving the check engine light came back on. I tried doing the pin short to see what error it would give me, but it didn't do anything.

I'm pretty much frustrated right now cause I can't seem to find a good mechanic in this area that won't screw me. but does anyone have any idea what could be causing all this.

Also here's the slip they gave me at the track....

Run 1 (in D) (first time ever on a drag strip)
----------------
R/T - .412
60' - 2.687
330' - 7.689
1/8 - 11.708
MPH - 61.90
1000' - 15.146
1/4 - 18.026
MPH - 79.46

Run 2 (in 1 -> 2 -> D)
----------------
R/T - .439
60' - 2.383
330' - 6.728
1/8 - 10.233
MPH - 70.93
1000' - 13.425
1/4 - 15.880
MPH - 86.11

Run 3 (in 1 -> 2 -> D)
----------------
R/T - .774
60' - 2.350
330' - 6.736
1/8 - 10.265
MPH - 70.75
1000' - 13.288
1/4 - 15.856
MPH - 87.83

 

had the same prob w/my 94. sold it. oxy sensor?

 

wish I knew of a place to get it scanned, right now I"m trying to get the cables to hook up my laptop to it but not sure what program I should use. I reset the PCM (computer) again today after those problems at the strip last night and now it's back to running good again. Except for the transmission jerking when I put it into (D)

 

quick update. had alot of people tell me that this problem was caused by my oxygen sensors. but while in the process of get those O2 sensors I went ahead and put a Jet stage 2 Module (for auto) computer upgrade/replacement bypass and now my car is running great. don't know why or what this computer mod did but it's fixed everything except the low pressure fluxing.


-madcat

 

If this is happening after the car gets to full running temp I would check all the vacuum lines off the intake and TB. If they have never been changed they can collapse when they get good and warm under extreem vacuum like at wot. This will cause sputtering and cutting out as you describe to.