My 2005 chevy colorado z71 ls, the check engine light is on constantly, and flashes sometimes. Was idleing rough, had diagnostics done, show misfire cylinder 5. figured it needed atune up changed all plugs and end up changeing coil pack on pack on 5 didnt do a thing same sh*t engine light still on and flashes sometimes, one of the codes im getting is u1026! any answers

SOURCE: 2005 chevy colorado runs rough and gets bad gas mileage.

Sounds like it needs spark plugs and wires, and a fuel system treatment.

SOURCE: Check engine light comes on. p0171 and p0351 codes found

From Lusty Kid:

I know the economy is bad, but change all of the plugs. Check your PCV Valve hose, 150 rottens them out allowing air to be sucked in, thus all kinds of codes.

Depending on mileage. Dismount the EGR valve and clean passages. If you are really good dismount the throtle position sensor body and clean out passages with Choke Cleaner., dismount where the EGR valves connects to the engine, clean out passages. Also check the hose thats behind this mounting to ensure is not clogged. If clogged clean it out. If not replace it. Is about 1.5 ft. long, connects to the PCV Valve Hose.

When is the last time you change your harness. Can't remember??? Replace it. Good Luck

Christian

• 53 Answers
• Posted on Dec 29, 2008

SOURCE: #5 cylinder misfire

I have a corolla and had #4 cylinder misfire also diagnosed at autozone. After changing the spark plugs, problem persisted, along with the same error code, so they recommended changing the spark plug wires, and that is what fixed it. I would have changed the rotor cap too, but was low on dough. Glad that was not the problem.

SOURCE: engine code p0307 cylinder #7 misfire

It could be carbon deposits on valve seats keeping valves from totally closing. You can try getting you a can of motorcraft PM3 top end engine cleaner and get engine up to operating temp then remove one of the small vacuum lines from the intake and draw the contents of the can slowly into the engine.After you have drawn in the contents shut engine off and let it soak for about 45 minutes then crank it back up and let it run until it clears. Now it will smoke like a forrest fire while you are doing this so don't be alarmed,just tell the neighbors you are spraying for mosqitos.This may cure the problem. If not you may be looking at a valve job.
This can be verified with a compression test if this is what is causing it.

SOURCE: 2000 toyota 4runner pulling a random misfire in

try a new crankshaft sensor not hard to change 2 bolts and a wire