My motor is beginning to surge real bad, especially when its not quite to full operating temp, but it bucks back and forth with the throttle in a constant position.
Here's my ideas of what it could be:
1) Bad distributor or not enough spark
2) Bad TPS sensor not reading constantly (can easily verify this with scan tool but have not)
3) Not enough air flow into cylinders??
4) ECM programming is just way out of tune with mods (its basically a stock chip, but lots have said they worked fine w/ZZ4)
5) Heads just not compatible with TPI setup (They are Worldcasting Sportsman 200s)
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My FP is right about 43# line off and seems to flucuate correctly.
New plugs and wires are on it also.
Other than this I have no idea, my motor is new, less than 5k miles on it, ZZ4 shortblock/cam, WC Sportsman200 Heads polished, stock TPI intake with some porting and polishing, Thorley headers, stock 22# injectors.
Thanks

 

Vacuum leak.:lala:

 

I had a '90 IROC that acted stoopid like that. It was a mixture of a faulty TPS sensor and a fuel pump that was going out. Replaced both and got right back on the road.

 

Thanks, I'll hook up the vac gauge and see if its any different than it was before, it pulled about 14-15hg before.
The fuel pump was brand new last year, has about 9k miles on it, and the fp is not irradic when this happens, so I'm going to rule that out for now

 

Vacuum-check all hoses and try go get a vac readiing, though may no show much with surging.
TPS-Use a DMM to check for smooth reading change with no flat spots from idle position through WOT.
IAC-Assure the pintel & bore a are clean and set properly.
MAF-Could be the problem. First verify the wires glow red for 2sec after shut off, if not a new burn-off relay is in order; if so, suspect the MAF.

 

Thanks for the info Jim, its funny, sometimes it runs great like this morning going to work. I'll start driving around with the DataMaster hooked up. Its not surging at idle, only during light accell and 30-40mph cruise so I wouldn't suspect the IAC in that case.
I forgot to mention I have speed density TPI so I can rule out the MAF, I ment to put that in early and forgot.
Thanks.

 

Sounds like when my MAF went out.