Strange behavior

[Alak]

My truck doesnt seem to idle steady. Like it works normally, but strangely. It will idle normally at normal RPM a little lumpy, and sometimes it will stall outright. When driving, there is almost no power under 1800RPM, soon as you hit 1800 is like 100% power so cruising is fine.

Transmission service maybe ?

[auwesman]

No codes? No SES?

[Disco Mike]

What year, model and mileage??
Can you better describe exactly what the truck is doing, lumpy doesn't help.
Mike

[Alak]

2002 DII (Coil Sprung).

145,000kms


So when it idles, its normal, only you can feel its a tad rough, not as smooth as usually. Nothing to normally be concerned about. Sometimes when I pull upto a light, or start it when its hot, it wants to stall. It will drop to like 100RPM and try and save itself. Sometimes it will, sometimes it will stall. If I keep my foot on the gas a touch, it wont stall.

When driving, normally I can just feather it, like 25%, to accellerate. I now have to give about 75% throttle to get it moving, then once it hits 1800RPM, it "kicks in" and everything feels normal, and power is 100%.

There was an SES light. Long story short, the Air Filter was completely plugged. The SES light threw a MAS code, a Vaccumm Canister Code and two O2 sensor codes - one for each side. We thought it was a result of the plugged air filter. We changed the filter, obviously, cleaned the MAS and reset the codes. They have not returned - HOWEVER, I may replace them in any case.

I know Im due for a transmission service, but I donno if its the cause of the 1800RPM thing. I only mentioned it because Its the only thing I havent really looked at, other than to check the fluid level.

[Disco Mike]

When was it last tuned, plugs and wires?
You can't clean a Bosch MAF and expect it to function so plan on a new MAF for starters.
Can you give us the exact fault codes?
Mike

[auwesman]

yeah, my "guess" was a MAF problem, but you would normally have some codes to indicate that, thats why I asked if you had any codes. As Mike stated, you're probably going to need a new on now whether that's the problem or not.

[Alak]

I was wrong about the codes, they were fuel mixture codes. I did a tune-up about a month ago, plugs and wires.

We replaced the MAF with a new (used) one and it works 100% now.

I've also serviced the transmission and noticed an improvement in shifting.

What else. I replaced all the idler pullies and the tensioner. I think the alternator bearing is going. Anyone know if theres somekind of warrenty on them? Mine looks like a brand new genuine unit. It howls like a bastard.


Other than that, everything has seemed to return to normal. I took the time today to remove the upper portion of the airbox and intake pipe to have it cleaned.