96 explorer rough start up runs fine once warm

[cssm]

I have a 96 explorer with about 200k miles on it. Recently it began to squeak while running, I assume a slipping belt but haven't had time to check it out. Not long after that started, at start up the engine sounds like a go cart and occasionally it will shake the car. Its fine once I get the car moving, but not if I don't get the car up to 40mph First. I'll take it into a shop if necessary but I'd like ideas on how to fix it myself if it's not a difficult one. Any ideas? And thanks for the help.

 

[PAExplorerXLT]

Rough idle from cold start is one of the more common issues I read here. I have one and my mechanic after much time and money couldn’t figure it out. Everybody says it is a vacuum leak somewhere. Happy hunting.

 

[koda2000]

What engine do you have? SOHC V6, OHV V6, or V8 (was the SOHC even available in '96?)

 

[Greg_DonWindsor]

Replace the left and right hydraulic chain tensioners. Before startup when there is no oil pressure, the piston acting on the chain tensioner relies on spring pressure only to pressure the timing chain sets. Over time these springs weaken. When the weather is very cold, oil has drained back into the pan and is thicker due to the colder temperatures. It takes a few minutes and tapping the throttle a few times for the truck to find it's revs. Once this happens the chain tensioners now have oil pressure and are much firmer with the hydraulic pressure built up. The condition seems to worse the colder it gets. If you change to new tensioners the spring pressure is greater before the oil pressure builds up, maintaining proper timing on cold startups.

Applies to 4.0 SOHC. I fought the same issue several winters.

 

[joe doe]

since this is a 96 it more n likely has a ohv engine ,although the op didnt say . that said if you have a rough idle apon a morning cold start that gets better as it warms up then i suspect you need to replace your upper plenum intake orings .
they are just right under the upper plenum . although when these do shrink you usually get lean codes . you got any codes popping up?