97 S10 Rough Idle

[Matto5]

I'm having trouble with 97 S10 idling rough, using more fuel then normal, and also lack of power/acceleration. It has 136,000 miles on it and I just took it in for a tune up when it first started showing signs of running bad. The shop replaced the plugs, wires, cap and rotor, but this did not solve my problem. The mechanic checked for intake leaks, and also suggested to run fuel injection cleaner through a few tanks of gas which did not seem to help. I've replaced the PCV valve recently, but haven't checked the EGR valve yet. The Service Engine Soon light is on and I was told by the mechanic that the computer was saying random misfire. The other thing that has me worried is that when I let it idle in the driveway, there is a black puddle under my exhaust, looks like carbon and water mixed, I don't think it's gas. I just had a new exhaust put on about 1000 miles ago and it's done this ever since. At first I thought it might be the new exhaust just breaking in and cleaning out any residue left from the factory but I think it would have stopped by now. Is there any way of telling if the cat is plugged or not working correctly. I've had this truck since highschool and love it, I've kept up with the maintence schedule in my Chilton Manual and try to take care of it the best I can.

Thanks for any help,
Matt

[Matto5]

Forgot to mention it's 4.3 Vortec.

[dmbrisket 51]

did they change plugs??? and if the cat was going, one way to tell is to run it hard, then get out, that smell like something is burning up is your cat going bad, if no smell then its not, also the cat can make a humming sound, to me it sounds like a fuel pump prime kinda, if thats a sound you have, your cat needs replaced or if emissions laws dont stop you take it off and get an 02 cheater from www.jegs.com

[Mikado14]

check for coil arcing at night in the dark.

[Matto5]

I don't see any sparks or arcing in the dark. The rough idle only occures when the engine warms up about 3 min after starting. When I'm waiting at a light I can smell a strong exhaust smell, but it doesn't smell like it's burning.

[BlazerLT]

Originally Posted by Matto5

I don't see any sparks or arcing in the dark. The rough idle only occures when the engine warms up about 3 min after starting. When I'm waiting at a light I can smell a strong exhaust smell, but it doesn't smell like it's burning.

Go get the codes read again at autozone and come back with the exact code you are getting.

Chances are it could be the coil or the fuel pressure regulator.

[xtrememeasures10]

Originally Posted by Matto5

I don't see any sparks or arcing in the dark. The rough idle only occures when the engine warms up about 3 min after starting. When I'm waiting at a light I can smell a strong exhaust smell, but it doesn't smell like it's burning.

The 4.3 has a common problem with idling rough. Take off your intake hose leading to your throttle body, take some break dust cleaner you can get it at an auto parts store, its in a spray can. Clean off the throttle plate and spray some down inside the throttle body. Run the engine for a couple minutes. Then rev the engine up to 2,500 rpms and hold it there until the white smoke coming out of your exhaust is gone. a lot of the time carbon deposits clog up the intake valves and throttle body. In worst cases the 4.3's throttle actually will become stuck open because of so much carbon build up! i bet that would be scarry. n e way maybe thats the problem. I do that to cars at my work everyday when they idle rough. If that doesnt work you might want to take it 2 Valvoline Instant oil Change n have them do what is called a performance system three on it. its kinda the same thing that i said earlier but it will clean off the whole intake manifold and all the intake valves. Peace

[BlazerLT]

Holy jesus man, what the hell are you asking them to do!

You NEVER spray brake cleaner into your throttle body!!!

You use throttle body cleaner, it is made for that job.

MERCIFUL CHRIST, WHERE DID YOU GET THIS CRAP PIECE OF ADVICE!

[dmbrisket 51]

the strongest stuff you should put in your MOTER is carb and choke cleaner and if you dont have a carb i wouldnt stick it in your throttle body or multi port, if i knew how to quote i would so quote BlazerLT

[Matto5]

I stopped back by the local shop again, and he seems to think it's related to fuel injection (CSFI) poppet valves and that I need to take it to a dealership to have the fuel system professionally cleaned. He printed out a service bulletin from Chevy, Ref Number 00-06-04-003B that explains that a deposit build up on the CSFI poppet valve ball and seat may cause the poppet ball to stick open or closed causing cylinder misfire condition. He also said that the misfire is only on the one row of cylinders. Does this resemble anyone else's problem, I want to be sure this is the problem before I spend the money to get it fixed at a dealership. Would there be any other way to correct the problem.

Thanks,
Matt

[BlazerLT]

Go get the codes read before you do anything.

[Matto5]

Originally Posted by BlazerLT

Go get the codes read before you do anything.

I was told the code was just a random misfire. He didn't give me an actual number.

[BlazerLT]

Having it checked again at Autozone and get the actual code.

Do that before you spend the money for the whole cleaning, it could be one injector that is fouled.

[tu=ppc]

Found this forum and thread while searching for a solution to very similar symptoms with my 98 2.2L S10 (~130,000miles.)

A _slightly_ rough idle has been present for many months. Within the last two weeks - power/performance dropped rapidly (still idles OK). Now, vehicle is really sluggish, won't accelerate much past 3500rpm, and bucks badly at constant speed - 35mph/3rd - bucking stops if I step on accelerator. Bucking is worse in lower gears. Battery is fine. Fuel filter is new. Only engine code was AirIntakeTemp sensor (P0113) high - which I probably caused by forgetting to reconnect. Spark plugs must have at least 40k on them.

I've purchased new plugs after reading this thread, but because the problem worsened so quickly, and because it doesn't run rough (like non-uniformity between cylinders/plugs/injectors), I doubt the new plugs will solve problem. It seems like a problem affecting all cylinders.

Any help/insight would be appreciated

[BlazerLT]

Originally Posted by tu=ppc

Found this forum and thread while searching for a solution to very similar symptoms with my 98 2.2L S10 (~130,000miles.)

A _slightly_ rough idle has been present for many months. Within the last two weeks - power/performance dropped rapidly (still idles OK). Now, vehicle is really sluggish, won't accelerate much past 3500rpm, and bucks badly at constant speed - 35mph/3rd - bucking stops if I step on accelerator. Bucking is worse in lower gears. Battery is fine. Fuel filter is new. Only engine code was AirIntakeTemp sensor (P0113) high - which I probably caused by forgetting to reconnect. Spark plugs must have at least 40k on them.

I've purchased new plugs after reading this thread, but because the problem worsened so quickly, and because it doesn't run rough (like non-uniformity between cylinders/plugs/injectors), I doubt the new plugs will solve problem. It seems like a problem affecting all cylinders.

Any help/insight would be appreciated

Please create your own thread on your problem out of respect for the thread starter.

This thread is to help him with his specific problem.