My Jimmy is not running too well!

[DaveCowley]

I need some help with diagnosis. Sometimes it will run for 20 mins or so with no hickups or anything and other times it wants to die every time I slow down to a stop light or what have you. Sometimes it takes a while to get it running again too. I changed the fuel pump and the problem still exists. No check engine lights or codes. Injectors pulse when you crank it and yet it doesn't run.
By the way it is an 88 TBI 350.

Thanks
Dave Cowley

 

[ZonkRat]

Check for vacume leaks.Does it idle faster than normal before being driven a while.Vac leak will cause TBIs to lean out.spray WD 40 around the throttle body while runnung.If it speeds up there's a leak.I've had two T B gaskets start leaking on mine.First one drofe me crazy for a week before I found it. /forums/images/graemlins/thumb.gif

 

[schmuck]

dose it have a coolent temp senesor if its bad it will tell the computer the the engine is running to hot or to cold and the truck will try to kill especaly before it warms up

 

[uglychevyZZ4]

get an ohm meter and a manual for specs and check the following:
TPS *throttle position sensor*
IAC *Idle air control
EGR *duh*
also, have you actuallt tried to pull codes? disc.. battery and then go for a test drive, freeway, and letting it idle till it dies a few times. ) and then recheck for codes.
( and all base or part gaskets / vacume lines, especially the ones linked to the heating system since ita all vacume )
MODULE * also the module leads and ring in the dist....

 

[89K1500Chevy]

Mabey the timing is off that will cause that prob as my truck did that it got loose i guess and set itself 26 degree's advanced and ran like [censored] well it was cool when it did not die like i had a big cam in it but it would shut off when going to stop just like yours. /forums/images/graemlins/deal.gif /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif www.zombieoffroading.8m.net

 

[DaveCowley]

Thanks for the help, I will check for vaccuum leak, EGR is bypassed and has been for a year. I have changed IAC and TPS. As far as timing it runs really well, just how it should. It dies only at very spurratic and intermittent times. I pulled the codes on it and the only code it is pulling is a Knock sensor code. I only get this once in a great while. It has been there for a few months also. So I don't think that it is the culprit. Any more suggestions?

Thanks
Dave Cowley