TBI stumbles at idel

[ggenovez]

Hi all,

I have a 90 burb 350 R5100 2wd TBI and I've noticed it wants to stall in gear while I'm waiting for a red light.

Idles along then then rpm's drop, stumbles, comes back up, rinse and repeat.

I've recently had a bad CTS and TPS so they are new.

Any thoughts?

 

[4WDKC]

check fuel pressure, get a scanner or make your own cable .

 

[1987 GMC Jimmy]

If you want to try parts, the IACV might be your guy, but a scan of your serial data would be revelatory in your situation. There’s a stickied thread in the TBI section on how to make your own cable. I’d also like to know if there were any serious vacuum leaks going on.

 

[Charlie]

 

[ggenovez]

Thanks.

Fuel pump is new. Tested recently at 13 PSI.

When you say build a cable is that something beyond jumping pins 1 & 2? It's a ALDL conneciton

 

[Jppr26]

Check your idle air controller

 

[gmbellew]

i had similar symptoms and it turned out to be the early signs of a failing intake manifold gasket. it would drive fine, but sitting at a stoplight it would do as you described.