surging 1994 Chevy Suburban

**mudpuppy** · 12-02-2008, 01:34 AM

first of all yaayyaayaa im back. now here it is i got a 94 burban and when not in gear the idle jumps about 200-500 rpm. only while not in gear. or atleast i cant notice it when in gear. no its not a vacume leak. me and 5 others have checked it for that. every sensor is new. new fuel pump and psi checks 5.0. timing checks 5.0. new computer. no codes popping. just about the only thing left is the injectors, what do you guys think?

**Steban** · 12-02-2008, 01:44 AM

my first guess was a timming issue but you said you already checked that. what about your TPS sensor?

**ct9a** · 12-02-2008, 01:46 AM

Could be the injectors if its a TBI 350. Supposedly they aren't matched very well at all from the factory.

**daddytech** · 12-02-2008, 01:47 AM

Have you had someone check out the transmission ???? might look at that if you have checked everything else out and its all ok. I would have also thought about the TPS or Map sensor, sometimes those will show no codes and still not function properly , just a thought.

**Steban** · 12-02-2008, 01:54 AM

Originally Posted by daddytech

Have you had someone check out the transmission ???? might look at that if you have checked everything else out and its all ok. I would have also thought about the TPS or Map sensor, sometimes those will show no codes and still not function properly , just a thought.

sometimes there is a fluke in the sensor. the best way to check it is you use and analog meter and chek the ohms values while you move the sensor. if something is wrong you see the needle jump or dive.

**ct9a** · 12-02-2008, 02:09 AM

Also, I don't know if the GM trucks have this problem or not, but on some of the motors that I'm used to working on an air pocket in the coolant system will cause this as well.

**vncj96** · 12-02-2008, 07:31 AM

I cant remember but does that have a MAF sensor or IAC, my old cavalier had an IAC and when that would get gummy it would idle rough easy clean with carb cleaner though

**mudpuppy** · 12-02-2008, 10:53 AM

maf and tps senors have been replaced tring to fix this prob and no resolve

**mudpuppy** · 12-02-2008, 10:22 PM

the tranny is a 4L60e, if 1 of the elect valves are bad wouldnt that pop a code or is there a differant way of checking that? i will say(it hasnt done this for some time now) it has had problems downshift when coming to a full stop. i was told it might be 1 of the elect valves in the tranny, not sure how they would or even might effect the idle though.