88 350 TBI cold start stumble.

[Supercharged111]

Just did a cold start. Still did 3 stumbles within first 20 seconds. Starting coolant temp was 28 on scanner. Watched MAP numbers closely and they constantly move a small amount. No noticeable difference during stumble.

One thing I’ve forgot to mention. When it first starts it around 1125 RPM. It gradually rises to 1200-1250 within the first 10 seconds.

Can you post a video next time?

 

[Steven Petersen]

Can you post a video next time?

Yes, good idea.

 

[Steven Petersen]

One other thing. I noticed today before I started I was down between a cup and a pint of coolant. It’s loosing this much in about 700 miles. I can find no evidence of a leak. No water in oil. No sweet smelling exhaust or white smoke.

 

[PlayingWithTBI]

I noticed today before I started I was down between a cup and a pint of coolant. It’s loosing this much in about 700 miles. I can find no evidence of a leak. No water in oil. No sweet smelling exhaust or white smoke.

I had pretty much the same issue - it turned out to be blown head gaskets. i hope that's not your issue.

 

[Steven Petersen]

I had pretty much the same issue - it turned out to be blown head gaskets. i hope that's not your issue.

Did you have any other symptoms?

 

[PlayingWithTBI]

Did you have any other symptoms?

Yeah, it started running hot in the summer.

 

[Steven Petersen]

Yeah, it started running hot in the summer.

I bought this a year ago and the water use has been very slow but constant. I made it through all last summer without any overheating. Actually the opposite, I was surprised how it hardly ever gets warm enough to engage the fan clutch.

 

[Supercharged111]

Yeah, it started running hot in the summer.

Well you live in AZ, so there's that. . .

 

[Maurice Evans]

Still fighting this thing. I got rid of the idle surge, it was the heat stove flapper in the air cleaner being stuck open. But I’m still getting 4 or 5 stumbles when it’s on fast idle 1200-1250rpm. After that everything is perfect. This morning I disconnected the evap canister from the TB and plugged the vacuum port. Still stumbles. All ignition parts are new Delco. New fuel filter. No changes in scanner readings when it stumbles. I have a new TPS arriving today, and new EGR valve and MAP sensor coming next week. Anything else to try?

 

[Maurice Evans]

TPS fixed my 95 Tahoe.