Rough Idle at start

[palaoan]

I've been trying to troubleshoot this problem with my 97 2WD, any help would be great.

It idles rough when starts, and after a minute it's smooth and normal. I've done the following but still have not alleviated the problem:

changed plugs and wires
changed 02 sensor (twice)
added fuel injector cleaner
changed gas stations
cleaned air filter (K&N)
replaced the throttle sensor (1 year ago)

The check engine light does not come on and it only happens after cold start. Lately I've noticed it happening after I leave the truck off for less than an hour.

Should I clean MAF or take it in for service and professional help?

 

[palaoan]

No none replied but I found out the problem. I thought I'd share it just in case anyone runs into the same thing.

Rough idle was due to coolant in the head, which ended up having stress cracks. I bought a new head for about $500, not including the machine shop cost to resurface, seal, etc. That totalled about a grand.

I thought it was the MAF or the 02 sensor initially, but it turned out to be something bigger and more expensive.

I hope this helps anyone in the same situation.

 

[mikes4runner]

What engine are we talking????

Your Headgasket went up?

How many miles??

Something doesn't smell right.....




Mike

 

[palaoan]

It's a 97 4cyl. 2.7 3RZFE 130K miles.

When the head came back from the machine shop, I saw the cracks.
Coolant leaked in the head, which was the cause of the rough idle when it started.

I was just pointing out that if the sensors are replaced, 02 and MAF, and the problem persists, it could be a sign of a bigger problem like it was for me.

 

[Finelygotone]

Do you know if that engine had ever been overheated? Were the cracks around the exhaust valve seat?

 

[palaoan]

yes. the cracks were along the valve seats and it was an overheating problem.