It has an off idle stumble and likes and acts like it's going to die, but you give it gas and it takes off fine. Driving down the road if you let off the gas it acts like it's going to die again. I changed cap,rotor,distributor, idle air control, ignition control,throttle position sensor,fuel filter, and fuel pump, and egr valve. I'm completely stumped and it shows no codes. If any one has an idea or has had the same problem let me know what fixed the problem.
2007-06-22 16:39:10 · 4 answers · asked by Candi D 1 in Cars & Transportation ➔ Car Makes ➔ GMC
I own a shop, and think it can only be a few things that would cause this. Ignition timing, vacuum leak, fuel pressure regulator, or low reference voltage to the throttle position sensor. Try this; purchase a can of electronic cleaner at the parts store, and clean every connection you can get to on the sensors, and check the pins in them for a bent one. Set the ignition timing, check vacuum hoses where they plug on for splits or just a bad hose. Clean the battery cables, the ground strap from the body to the fire wall, and any & all grounds that the engine may have. Purchase a can of STP fuel injector cleaner (black bottle only) and add that to about 3/4 of a tank full of fuel. I'll bet this fixes the problem. Another thing that can cause this is; a dirty throttle body. If you clean it, stuff a rag down inside the intake to keep the crap from getting into your EGR, and/or the O-2 sensors. My wife has a Blazer that has throttle body injection, and if she doesn't keep injector cleaner in the tank at least once every month, it does the exact same thing. The timing may be off, and will in fact do this exact same thing too. Keep digging.. You'll find it.
If your vehicle is equipped with a mass air flow sensor, clean it an that will fix the problem. It is possible the problem is in the ignition system, wires, or bad spark plugs. I have seen a crack in the insulator (white ceramic part) of a spark plug. It is easy to crack one of these while installing a new set of plugs. Removing the spark plugs one at a time, and looking at the electrode will tell a lot about where to look, and if you indeed have a fire problem. It will show up as a very different looking color as the plug not firing properly.
Glad to help out, Good Luck!!!
2007-06-23 02:19:24 · answer #1 · answered by Anonymous · 0⤊ 0⤋
I would first make sure you don't have any corrosion on the internal part or the spark plug wires or the coil wire. If there is any suspected corrosion, replace all the wires and if there is corrosion evident on the coil tower, replace that as well. Also check plugs for being worn out or for carbon tracking or corrosion too. Replace as necessary. I would make sure the gasket under the TBI assembly is not torn and leaking or plugging off the IAC port as these had a tendency to do this. the other thing you might check is the validity of the coolant temp. sensor. These would get off kilter as they sit in a corrosive antifreeze and can become corrupt without setting a code. They can read high or low and that makes the motor run funny. Good luck.
2007-06-23 08:09:49 · answer #2 · answered by Deano 7 · 0⤊ 1⤋
Make sure theres spark to the plugs...You didnt say you changed them you might try that.
2007-06-22 16:49:15 · answer #3 · answered by snowlady 5 · 0⤊ 1⤋
spark plugs. compression.
2007-06-22 16:55:08 · answer #4 · answered by matt 2 · 0⤊ 1⤋