Please help! Idle issues now.

[Mean Green]

I sure hope not, but perhaps a leak in the intake manifold gasket. When I cranked it tonight and left it running while checking the injectors tonight I noticed what appeared to be a lot of smoke coming out of the tailpipes, but it was white and I believe it was steam based on the amount of water coming out of the tailpipe. It dropped about a 3" diameter puddle on the ground in about 5 minutes, and had a very slow drip, but a drip none the less, after I cut it off. The smoke nor the water on the ground smelled anything like coolant though, and it has mostly good new coolant in it.

Not good. Was it damp outside? Or cold? Condensation is normal, but the amount of water left on the ground you described is not. Your deffinatly going to want to moniter your coolant levels, and check for any water in your oil. Could very well be a intake or head gasket on it's way out. A compression test may not be a bad idea to rule that out if possible. Also, I may have missed this earlier, but have you checked the pick-up coil in the distributer? That can cause all kinds of weird idle related problems, and the87-94 TBI pick up coils in the distributers are very prone to cracking and causing problems!

 

[milky9788]

Ok so its pretty much the same thing but with a different pin setup in the connector, I actually bought that one when I meant to get the block one and had to exchange them. I'll pick one up tomorrow, couldn't hurt to change it.

Two other possibilities I'm thinking about:

1) I put 8 ounces of MMO in the gas tank Sunday too on about 15-18 or so gallons of fuel, I'm wondering if maybe it broke loose some grime in the fuel tank or fuel pump and sent it down line to the fuel filter. I've got a new filter I've been meaning to throw on, weather permitting I'll do that tomorrow.

2) I sure hope not, but perhaps a leak in the intake manifold gasket. When I cranked it tonight and left it running while checking the injectors tonight I noticed what appeared to be a lot of smoke coming out of the tailpipes, but it was white and I believe it was steam based on the amount of water coming out of the tailpipe. It dropped about a 3" diameter puddle on the ground in about 5 minutes, and had a very slow drip, but a drip none the less, after I cut it off. The smoke nor the water on the ground smelled anything like coolant though, and it has mostly good new coolant in it.

Yeah that look pretty much alike aside from the connector...Go ahead and change the fuel fillter before you try a new a CTS and see if that changes anything, but if not change the CTS...Are you losing coolant?...Oh yeah I forgot about the pick-up coil, check that out as well.

 

[bluex]

Could you have cracked a plug on installation? It seems really easy for me to do when that rubber piece is still in the socket. I did that on my '78 and it drove me nuts. I replaced all kinds of stuff except the plugs cause they were new. Finally replaced them and the one I cracked broke when I removed it. That was my culprit all along.....

 

[ChrisAU]

I think I have been losing a very small amount of coolant, maybe. Hard to tell really. Never seen a drip on the ground. I changed the oil less than 300 miles ago on the truck, and it did not have any water in it. It was black as hell, but didn't appear to have water in it. It appears some work has been done on this truck, by an amateur. There is some orange RTV type substance all along the intake manifold and the valve covers. I think its spitting a bit of oil out of the drivers side valve cover onto the manifold.



I just don't want to do all this chasing my problem when it appeared right after replacing plugs, wires, cap, and rotor. Just seems like that has to be it. I think I'll get another cap and rotor first, then wires. Ugh.


And I was very careful with the plugs on installation, turned them most of the way by hand, only snugged them up with a ratchet.

 

[ChrisAU]

Wait a minute...am I supposed to put di-electric grease on the contacts of the cap before installation?

 

[ChrisAU]

After research, I have determined that the pooled oil on the intake is not from the valve cover, but from the two bolts right there for the intake manifold. Its pretty obvious that the intake gasket has been done before, and also that they didn't put sealant on the center bolts. Also pretty obvious that the workmanship was pretty poor, and I actually don't have much of a doubt that they are leaking now. But that still doesn't solve the mystery of my rough idle after doing a tune-up, hopefully generous amounts of di-electric grease at all connections will do the trick. As for the intake, I'm thinking I'll dive into it starting next week and take my time, only doing an hour or two of work a day until I'm done...never removed a distributor, that's all I'm really nervous about, getting the timing right when it goes back on.

 

[ChrisAU]

Well the weather isn't going to cooperate today, hopefully next week I will ***** it out.

 

[ChrisAU]

Welp, replaced the fuel filter and put di-electric grease on every single point of contact of different parts that I put on for the tune-up Sunday (plug boots on both ends, ignition coil terminal, dist cap terminal, dist cap contacts). Fired it up and it ran great, took it for a test drive, it ran great. Got it back home and it started hiccuping (just now getting to the 190ish mark) and sat in front of my house and let it stumble while I held the brake in drive, and in about 90 seconds I'd say it cut off. Fired right back up no problem, but still stumbling. Seeing as how the problem got bad when it was warms up, I'm gonna go with the coolant temp sensor in the manifold next.

Here's a question though: Which way does coolant flow through the t-stat (I know, noob question...)? Does it flow through the hose into the manifold or does it open up and allow coolant to be forced through the hose and into the radiator? Only reason I'm wondering is because a sure sign that my intake manifold gaskets are gone is if it is flowing new coolant through the manifold when the t-stat opens, therfore making it idle bad if there is a leak when the coolant is moving (throwing coolant in the cylinders and killing it).

 

[ChrisAU]

Welp, new intake manifold gaskets, new coolant temp sensor, and new EGR Valve Solenoid, and I still have my idle/stalling problem when it warms up...any ideas???

 

[gmcyukondriver]

Spray around the intake manifold and throttle body with carb cleaner to check for vacuum leaks. My guess would be IAC, or a gasket leak of some kind. On the throttle body, there is a "bleeder hole" right near the IAC, check to make sure that isn't plugged. Crap can get in there, and block it off, and it affects airflow of the IAC.

My truck has done this twice before. First time, the K&N cold air intake gasket was getting sucked into that bleeder hole, and blocking airflow to the IAC. Second time, I had a vacuum leak in the throttle body gasket. Does it shake at all when idling? My whole truck would vibrate quite a bit.