sedrats

i have a 95 surburban. about amonth ago it started running real ruff. i took it to the dealership they put o2 sensors on it and told me the cadilitic converter was stopped up.i had a new one put on and it did not help.i took back to dealership and they put a new distibutor,fuel pump,spark plugs,wires,rotoe,cap and throttle body.i got it back and it runs a whole lot better but still has a miss. i took it to a friend,he put a coil on it.but didnot help,we tried to advance timing no luck,please help

GMMerlin

Check compression, Might have a weak cylinder.
Also check the EGR valve to see if it might be stuck open or opens up too much when you accelerate. This will also cause a rough running condition.

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Got all the certifications
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Yea..I work at a DEALERSHIP....got a problem with that?

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sedrats

thanks,one more thing the truck only runs rough once in a while,mainly during idle or sitting at a stop light, some slight hesitation at speed

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steve

GMMerlin

if its an intermittant problem, check the EGR...might be sticking open

__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again?
Got all the certifications
25 years ASE Certified Master Technician
GM WCT
Yea..I work at a DEALERSHIP....got a problem with that?

Want to diagnose cars like the Pros? FOR SALE: OTC Perception 2 channel Labscope (badged as a Matco Reality)
This is my personal labscope that I use to diagnose waveforms, like new, comes with leads and training video
PM Me for details

sedrats

checked egr not it thanks

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steve

jbb3rd

I have a similar problem in my 1996, and did all the work you did. Have you solved it yet?

Thx

sedrats

no not yet,just replaced distibuter and it ran fine for a couple days then back to the miss.please email at sedrats@attbi.com if you can help thanks

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steve

BSarte

I have had some of the same problems for almost two years. Diagnosed the hell out of it, put in alot of parts/sensors as well as money, and the problem still persists. It started about 2 years ago with a slight stumble and miss under acceleration. I have had it to 3 different dealerships, a supposed "GM" guru, and this morning I spent 4 1/2 hours with the guy who I trust the most, my old mechanic. I have replaced the injectors, O2 sensor, TPS, Dist module, Cat, MAP, EGR, ECM temp sensor, knock sensor, plugs/wires/dist cap & rotor, as well as to swap out the ECM and Memcal with known good ones. Problems still persists. This morning we came to the conclusion that it appears to be running lean according to the O2 sensor and why the injectors are not compensating correctly is still the mystery. Just before this problem started, the trans was replaced under warranty by the local Chevy dealer and one of the items they noted they did was to "update" the ECM. I personally think that my problem is with either a wiring harness issue (wires shorting) or with something in the ECM such as the "update" that was done. Anyone have any ideas as to how an ECM/Memcal is done? Is it like updating the bios on the PC? Did I get a bad update? ANy of these issues like any of yours?

Just my thoughts and problems with my favorite vehicle.

Bruce

systemt

Just bought a used 95 suburban 5.7 4x4 as is/no warranty. I have noticed the exact same miss/hesitation/occasional stall described here. Happens daily. Looks like I'll start with the EGR. Has anyone solved their problem?

Ted

MJW393

I had a similar set of symptoms on my 95, changed the fuel pump and all was well.

draston

had same prob, was my EGR valve...