97 LT1 holds 1800RPM after WOT

[9730thSS]

Guys, I've had this problem for quite awhile after a WOT run the engine comes down but sticks at about 1800RPM. the car was tuned by a pro 2 years ago. I have redone some things on the motor and also bought tunercats to learn/redo the tune in the car. With the help of my father inlaw(GM tech) we noticed many things(such as constants were weird) in the tunercats were a miss. We corrected things and the car runs the best it ever has except for this problem that we have now which is not new. We have even replaced the TPS on the BBK 58MM TB but it still does this. I used the tables that Soloman said to use in his tuning guide but to no avial. This weekand is tech day at Bandimere and this is the only thing that needs left to be done. Thanks for your help.....

[hotrod96z28]

could be a clogged cat causing to much back pressure making it engine brake.

[popo8]

What is at idle before a WOT pass?

[9730thSS]

my standard idle is 850RPM and it staggers down perfectly @ everything but from a wot run...

[popo8]

Do you have any vacum leaks? Something that may occour after excessive motor compartment heat....

[9730thSS]

none that we know of, the car runs perfect until you go through the gears at WOT. I can play with the tables all I want in tunercats and it still does it. I really think that its something with the BBK 58MM TB....

[popo8]

none that we know of, the car runs perfect until you go through the gears at WOT. I can play with the tables all I want in tunercats and it still does it. I really think that its something with the BBK 58MM TB....


well I am running the BBK and I had similar issues with mine. originally it would not idle high enough no matter how we attempted to tune it, so we drilled small holes in the blades and after that found an unrelated issue. Once the unrelated issue was corrected the idle would not come lower than 1200-1500 rpms at idle.... we epoxyd the holes shut which helped a lil, then manually lowered the idle with the idle screw to where we wanted it...

[TA the destroyer]

did you check you air idle control valve? maybe you plunger is getting stuck. use some eletrical spray cleaner.

[Pro-jection Eng]

i'm thinking sticky IAC as well...

[MoeHorsePower]

What is your IAC counts when it is doing this? also have you tried to blip the throttle just to see if it is sticking?

[ksmyss]

I had the same problem with an edlbrock/bbk 58mm tb. It would stick about 1/2 throttle. When it does it see if you can close the throttle body yourself. I took mine all apart and the damn butterflies were out of round and hung up on the sides not letting it close. I tried everything and nothing would work. A second return spring helped a little but also made it harder to push aswell.

I tossed that in the trash and picked up a new one and now have zero issues.

[trboZ28]

i have had issues with the opti double counting teeth causeing an issue like this
or a sticky IAC valve