la_ponchita95

well ive had my truck for a year now n i cant seem to fix my problem. i have a 95 silverado 350 truck starts fine but sometimes my idle can be a little crazy and when ur taking off it bogs the rpms go down like it wants to turn off and when i stall the engine the rpms go crazy the neddle go's up n down never stays steady ive tried everything i have a new tps sensor, cv sensor, fuel filter, cap n rotor, and still the same problem the obd scanner reads that the truck is fine plz can anybody help me?

by the way my truck has full bolts idk if that has someting to do with it?

la_ponchita95

i guess no one can help me

MyBowTieGuy

la_ponchita95,

If you're experiencing engine bogging as well as an erratic idle then I would hasten to say that you may need to either clean or replace your Idle Air Control Valve. However, first check the vacuum hose for dry-rot or cracks and make sure that it is clamped down tightly. If all looks good with that, you can move on to the idle air motor or valve. My dad was experiencing the same symptoms with his Silverado a few months ago so I helped him clean it. Here's how you would go about cleaning your Idle Air Control Valve:


Find the idle air, which is generally near the throttle body. Unplug the wiring harness connector. You may have to use the flat-head screwdriver to pry open the snaps. The idle air will have either screws or bolts holding it in. There are usually only two. Using the proper tool, unscrew the idle air from the block.

Examine the idle air needle (it is about as thick as your pinky finger). If the needle is black, it is dirty. That is carbon buildup. Using the carburetor cleaner, spray only the needle and wipe it clean. You will have to do this quite a few times to get all the carbon buildup off. Do not get carb cleaner on any of the electrical parts of the motor. You may not be able to get the idle air motor perfectly clean, but that is all right. Allow the idle air motor to completely dry before reinstalling it into your car.

Insert the idle air motor back into the block. Tighten the two screws down, going back and forth until they are snug. Do not overtighten them, as they could break off in the block. They just need to be snug. Plug the connector back in. Look to make sure you did not dislodge any other wires or the vacuum hose near the idle air motor.

Start the car. You may have to drive it a bit to see whether cleaning the idle air motor or valve worked. In the case of my dad's '97 Silverado, the IACV needed to be replaced so we snagged a cheap OEM replacement part from Chevrolet Parts - Genuine OEM Chevy Auto Parts & Accessories and called it a day

Another possible culprit behind your bogging/vacillating idle is the EGR valve. Inspect your EGR valve (or have a skilled mechanic do so) to determine whether or not it has to be replaced.

Keep us updated on the situation and best of luck to you!

la_ponchita95

MyBowTieGuy,

well i did what u said and i change my egr valve but for some reason the problem is still there my brother was tellling me is that i should check my fuel presure and that might be my problem having low fuel presure but i have a (Jet) ajustable fuel presure regulator i think im running about 15 psi so idk what to do now

thanks anyways

Chuzz

When's the last time you did a full tune up? Plugs, wires, cap, rotor button and PCV valve. You may have something as simple as fouled plugs. You should also look at the condition of your air filter and breather filter.