I've tried all i could.. I've check timeing, check tps, redid minimum air, gave it some fuel injector cleaner, check the spark plugs, checked the cap and rotor (a little green stuff in there, but i cleaned it and all, need to replace'em). I've checked the plug wires, all sending spark. Yet my car still studders, and bogs down, and if i press on the gas too much it'll backfire. Yet it won't do this all the time, but a good majority of the time so to make me hesitate on takeing it long distances. Another thing, after i get passed the studdering, etc, it'll run fine. I've also stuck a straight pipe in the cats place seeing if that would fix it. I've checked the coil. and vacuum lines. I just can not figure out what could be wrong. My only theory is maybe messed up FPR or Fuel Pump goin bye bye. How do i check both of those, and also any other suggestions? To add to my many upon many troubles. It's harder to start in the morning. I have to tap the gas to get it to start, and yes i let the FP prime 1st (i gotta set my books in the car, and get my shades on ya know! ) Yet it still is hard to start..any help is appreciated. Thanks Peeps.

Also, how might i check for a lean or rich condition? I doubt that could be the situation but i'd like to add it to my list of things checked..

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?

[This message has been edited by branz28 (edited October 19, 2000).]

 

You didn't mention that you replaced the fuel filter. That's classic symptoms.

 

I did change the fuel filter with a NAPA Fuel Filter, about 2 weeks before this happened, and i ported my plenum n' port matched my runners about a week before it happened.

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?

 

Could plug wires that are loose or makeing not good enough contact cause this?

------------------
89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?

 

your not getting any codes?

 

The plug wires could very well cause the afore mentioned symptoms. They are easily damaged when they are removed from the plug, if not done correctly you can pull the wire out of its crimp connector or at least loosen it and it does not take much to upset this connection and cause problems. Next time you install new plug wires put a little dielectric compound in the connectors to help prevent them from sticking to the plugs.

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"84Z28/'91 305TPI comp cam flowmaster TB coolant bypass/shutoff valve to heater core MAT relocated Ram-Air(home-made) gutted air-box IROC ground effects/wheels GY245/50's 700R4 superior shift kit/ corvette servo(excellent shift kit BTW) Rebuilt engine and transplanted it myself. Love this engine!
LOW performance people should drive low performance vehicles!

 

I'm having identical problems. Is the inside of your plenum black from the backfiring? Something inside may be clogged from carbon buildup. I'm about to perform that job tomorrow morning. I already did the throttle body and it didn't help.

Clean around the throttle blades as well. I don't know what else to tell you, but I'm interested in the thread if anyone else has ideas.

 

Another vote for weak insulation on the plug wires, cap, and rotor.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Welp, cap and rotor were just singled out today, bought the kit and no change. Man, i hope my MSD 8.5mm plug wires aren't shot. Spark plugs look fine...normal wear to them from driving. Also, i'm not hearing my fuel pump prime in the morning, or after it sitting for a while... Kind of scares me, but the car runs fine. On top of that, it doesn't hesitate, and chug, and stumble after 1500 rpms. It runs like it should. But if the rpms go below 1500, boy i better get my coal shovel and start addin more coal to the fire.



------------------
89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-Future:
-383 Stroker?