gwade12

Hey guys,
I've got an 87 2.8L. Just bought it a few weeks ago, so I've been updating/upgrading parts to try and solve my issue. I love it so far, I just wish it would idle better. So far I've done expensive plug wires, plugs, Accel cap and rotor, MSD Street Fire ignition coil, O2 sensor, fuel filter, and I also flushed my coolant system and replaced the thermostat. The air filters looked pretty new, and I've got the dual snorkel air intake. When coming to stops, most of the time the car will stall or come close to it. It also idles pretty rough. I've tried putting some B12 Chemtool in the gas tank with a full tank, cleaning the PCV, and cleaning the IAC. Today when ensuring the EGR is working properly, I noticed none of the vacuum lines running to or around it were drawing vacuum. When I unplugged the bigger piece that plugs into the back of the throttle body, I could hear it suck air in and the car died. But the ends of the lines aren't drawing in any air. I actually unhooked every end from that larger piece, and the car just kept running as it normally does. Sprayed some cleaner in the back of the throttle body and let it sit for a minute or so, then ran the car again. Didn't help though. I've found 3 vacuum leaks and fixed them, but that hasn't helped either. What do you guys think? My exhaust also rattles when the idle is being hesitant and dropping (from the catalytic converter specifically, which I plan on replacing soon). Thanks for any help, it's much appreciated. I'd love to have my car running as well as it can for being 28 years old.

gwade12

I've just tried cleaning the throttle body with some B12 and doing an idle relearn afterwards. Still no help. The idle is only slightly rough; however, there are times it will really dip low and the voltage will plummet, but then it catches itself. Right after it catches itself is when it seems to idle the best. At least, for a few seconds or so. Then it starts to get a little rough again. Could that indicate something specific?

gwade12

Yesterday when I was playing with those vacuum lines, I also unplugged my map sensor. It didn't change how the car ran at all, and I just plugged it back in. That seemed pretty odd to me.

Gumby

only 1 year newer, but mine is all different.

someoe asked about EGR hoses a few days back, dunno if you even have that.

https://www.thirdgen.org/forums/v6/7...tually-do.html

gwade12

I know my EGR valve isn't stuck, and I can't find any leaks in my vacuum lines. I looked up the solenoid on autozone, but it looks like they won't be able to get one. Does anyone know how to test if the solenoid is bad?

Ce84q8

the map sensor should make a difference on how it runs, make sure the vacuum line is connected between the two as well. if that dosent work and your idle is funky check the air/fuel. had to do a carb rebuild on mine

gwade12

What's the best way to check my air/fuel?

gwade12

I've gutted the cat because the front honeycomb was plugging it up a little. Since then I've experienced no stalling, but I've still got a rough idle. I'm thinking maybe my IAC is worn out or my MAP sensor is bad, but I'd like to check them first before buying a new one if there's a way. The only other thing I can think of is the oil pressure sending unit. When I bought the car they said it was leaking from the valve cover and would need a new gasket. After I bought it I found out it was just leaking from the oil pressure sending unit, so I replaced that. I can't remember it having a rough idle before replacing that. Could my cheap autozone replacement be giving me problems? Also, does the SES light need to blink EVERY time I have key on/engine off? I just got home from a cruise and went to check to see if there were any codes stored, and I noticed that my SES light didn't blink when I turned the key on. It usually does when I first go to start it.

gwade12

Installed a new IAC today. Helped just a tiny bit. Double checked my plug gaps. It's idling just a little better. I still can't figure this out. It almost acts like it has a small load on the engine randomly at idle. Gonna borrow a buddy's timing light and check my timing tomorrow. Hopefully bringing that down some will help. I'm sure it's advanced some. I'll update again tomorrow. Also gonna see if I can pick up a 93 dodge stealth in town that just sits for $500 tomorrow.

gwade12

Bumped my timing back to 10* when I got off work last night. Helped just a little bit, so my idle isn't too bad anymore. Still a little unsteady, but I'm not gonna ask much more from such an old engine. Just gonna try to hunt down any more vacuum leaks and then call it a day.

gwade12

Forgot to mention - a couple weeks back I ended up ordering a TB mounting gasket from Autozone. Took off my TB, cleaned it up good, cleaned as far back into the plenum as a could, and installed the TB with the new gasket. Didn't help much at all, but that plenum sure was full of carbon.

gwade12

UPDATE: Even though no one is responding, I suppose I may end up helping someone in the long run. After running 10* for a while the car got very sluggish on cold starts when attempting to accelerate at low speed. Decided to put it at 11*. My fuel pump has always whined while running. About 3 days ago, the car began making a weird noise coming from what seemed to be the rear end. I considered the fuel pump, but I could hear it clear as day near both rear wheels, so decided my rear brake shoes could've just been worn out. I could only hear the sound when stopped or coming to a stop. About a day after the sound began, my car stumbled when backing into my girlfriend's driveway. I didn't think much of it. Got back in the car about 30 minutes later to head to AZ to get brake pads and shoes. When I turned the key and heard the pump prime, I decided I probably wasn't driving my car to AZ. The pump sounded horrible. The car struggled to make it the 3.5 miles home. Now it will only run for about a second then dies. Considering a fuel pump is only $52, I bought one and will be replacing the current one. I am attempting the access panel method, so in a few hours I will be going up town to get some compression fittings. I will post another update after I get the job done. Hopefully my car runs like a top again and this solves my rough idle issue.