This is my first post. I have been reading the board frequently for a while now. It seems like you guys realy know your stuff. This little problem has been driving me nuts for a while now. When the car is cold it is hard to get it to idle( it likes to die alot). When I try to take off from a dead stop the car boggs down and then suddenly kicks in it also does this if I just jab the gas be it while driving are out of gear. At around 3000 rpms loud popping can be heard coming through the exaust. At full throttle the car seems to surge. It does not trough any codes. I have had some friends that work up at the chevy delearship take a look at it. They put it on the scope and tech 1 and could find nothing wrong with it. This has done this now on two different engines. My first engine consisted of stock bottomend, miniram, afr 195's, tpis zz409 cam, and all the bolton. The second is a stock crate motor from GM for a 93 caprice. It is stock execept for the addition of a slp cam i had laying arond I believe the specs are somthing like 207-212,480-487. I put the miniram on this motor along with all the boltons. Then car seemed to run fine on the new motor untill it hit about 400 miles on it, then the problem crept back up. The first engine took an early leave to the grave because of a dropping valve. I have tried changing the tps sensor, mass air flow sensor, ignition module, and swapping compurters and proms. If someone could please figure this one out for me I would appreaciate it.


Thanks

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1989 Irocz
350 T-5

[This message has been edited by STOCKROC (edited March 22, 2001).]

 

Did you take a look at the Pickup coil and reluctor while you were in the distributor? Check the reluctor for crack, check the PU coil for greenish oxidation under the plastic, and also in the connectors.

The cold start cold idle problem could be with the IAC, and/or the CTS, both of which should be tested through the ALDL with a scanner. You can reset the IAC and min idle, but without a scan tool, you can read the counts..the CTS can be checked with a ohm meter, I can dig through my manual for the #'s vs temp you should see.

What do the plugs look like, seem to be running rich or lean?

Popping through the exhaust is unburnt fuel reigniting, might be due to an ignition timing problem, or just too much fuel...how many miles on the O2 sensor? (O2 sensor should have no effect on the cold start though...)

Try disconnecting the MAF before the start up as well, and see how it runs. If you know the MAF is good, then a MAF relay (burnoff or power) could be bad.