cold running issue, searched and tested already

:roll: Well i've been on this site for a little while now and been reading up lots on various possibilities as to why my truck runs rough when it's cold,gets better when its warm but not 100%.

i have tested the following and all came up good,
map sensor - tested within except specs
coolant temp sensor - right where it should be
egr solenoid - tested good
tps sensor - was a little off but move it around and come up with the proper specs,good now
so all these sensor were tested good.

tested the o2 sensor was a little low, probably could use to be replaced but that wouldn't cause my issues,
the only thing i haven't fully tested is the egr valve but it seems to be working fine,plunger moves freely and truck almost stalls when i move the valve in and out. vacuum is getting to it, no problem there.

I'm starting to think that the timng chain could use to be replaced, truck has 296,000km on it and i have no clue if it's ever been done, plus sounds a little noisy in that area when i got my head under the truck. could be possible reason the truck has some issues, timing could be way out of whack and needs to be fixed.

Any insight and help into resolving this problem is greatly appreciated!!!

Thanx in advance!!!

88rubixj

do you have a K&N FIPK? Mine stalls sometimes when its too cold. There is such as thing as too much cold air. disregard if you are running stock airbox

Did you test the upstream o2 sensor? Im assuming an 88 has one, might not. When mine went it game me all kinds of problems, but no CEL. Bogging, stumbling, until the sensor warmed up a bit, then it ran fine.

stock airbox etc.. it's pretty much a bone stock truck except for exhaust and the lift etc

well tonight i changed the timing chain and gears, needed to be done badly had like an inch of slack, timing is better, throttle response is better once it warms up but still runs like a P.O.S when its cold,gets better when its warm but not 100%??

ANY SUGGESTIONS guys?

getting close to winter and it gets really cold up here sometimes so it'll suck if it ain't fixed by then.

PLEASE HELP!!!

I get the same problem just started fairly recently. It stumbles when you give it gas and let off. It doesnt die though.

nope, talked to a friend of mien, he said change the o2 sensor, i hate throwing money at this thing expecially when the end result doesn't fix the original problem, but i can imagine the thing needs a new one, truck has 296k and i don't have any kind of records on the truck

my truck used to run like crap until it got to full operating temp.

culprit was the CPS wires touched the exhaust manifold and melted/shorted out on each other.

i dont know why it ran ok once it got warm, but it was undriveable until then.

-Tim