What would suddenly cause the idle to go bad? It sounds lumpy and stumbles, speed fluctuates, sometimes stalls when warming up. Above idle, it runs well - good power, no backfiring.

There are new plugs and wires, fuel filter and air filter.

The TPS checks out OK, timing is OK, no codes. All vac hoses are intact and connected, I couldn't find any vac leaks.

I didn't check any other sensors, I don't know where to start. Can anyone provide a clue what the most likely sensor/problem is, and I can start there.??

'88 N/A

 

First and automatic guess is a vac leak. Not just hoses leak. Gaskets, the insulators around your fuel injectors, etc. I had a leak at my primary injectors. Now, thatnks to my own butterfingers, I broke the LIM gasket and have a raging leak there. No new gasket for me 'til Thursday...

What technique did you use to search for a leak?


edit: I'm partial to using water (garden hose) myself. It's free and you never run out and your rad fan doesn't blow the water away when it kicks in...

 

I sprayed carb cleaner on mating surfaces, also used the rubber hose-to-the-ear method to listen for leaks, and pinched each vac hose with needlenose pliers to check if it changed the idle.

 

Try a garden hose. Go one vac hose at a time and just let the water run over it for 10 seconds. Give it lots of time. I discovered that I was leaking at my primary injectors (grommets baked hard) when the motor would bog only when I held the hose over the TB. It was process of elimination and I *never* would have found that leak using a gas (like carb cleaner) or hose-to-ear.

Water is my friend.


Btw, the hose-to-ear thing has never well worked for me...

 

Yep it was vaccuum leak, big time. The intake-to-engine gasket actually squished out the front edge behind the airpump. This happened 8 months after reassembly. Beware paper gaskets (and probably over-tightening). The good thing is I'm getting really fast at tearing down and replacing the intake system. I'll post a pic if this thing ever lets me....

 

 

was part of the gasket actually sticking out? cuz, i see a piece of paper gasket sticking out from between LIM n engine just like you. and idle sucks, it stumbles @ 500, sometimes steady @750. but most of time, stumbling.

where in rockville u in? i'm by shady grove rd.

eddie

 

It was sticking out just like that when I took off the LIM. The paper gaskets are garbage. I found the leak by rechecking with the rubber hose to the ear, and it made a strong hiss right where the gap is. And I'm 10 min. from Shady Grove.

 

there anything besides paper gasket? the one from madzatrix seems to be paper.

 

I picked one up at Rotary Performance out in Manassas. It's a nice 3-piece one with a metal layer in the middle. Mine is a n/a and they happened to have a couple laying around. Not sure if they have turbo ones in stock but it's worth a call.

 

yea, rick, i think, installed my last reman... hmmm you would think he would use the one u got... nevamind. i'll give him a call n see wats up.

 

hey guys, I also live REAL close to shady grove, in fact, I walk to the metro all the time... (I live off of Needwood road) I am just getting into my 7, and am having some problems... I have another friend here who has been a great help, but the more help i get, the better... if you guys want to meet up some time, let me know. I work at Chesapeake Knife and Tool at Lakeforest mall most weekends too... I would love the help...

~Andrew

 

hehe... i used to live by blueberry park. now i live by redmill center... PM me... we'll get together sometime.

eddie