95 5.0, Big "Miss" at Idle, Won't go past 1000 RPM under load

[SAC81]

For the past year my 95 5.slow has been running like a champ. Decided to take it for a joy ride last night. It started out OK; I noticed a slight miss at idle, but over the years my car's done that from time to time when it's sat for a while so I didn't think much of it.

Anyway, as the car got warm, the "miss" got worse and it started to "stumble" and hesitate a bit at lower RPMs. Once past 2000, it seemed to pull normal. I decided to head for home. Heading up a hill close to home, the car would NOT rev past 1000 RPMs and was bucking/shaking badly. The check engine light came on. I barely made it up the hill. I finally got it home, where it stalled in my driveway just in front of the garage. I started it up to try to pull into the garage, and it was very, very "choppy" at idle (sounded like I had a big solid lifter cam or something) and lots of black/gray smoke was coming from the exhaust.

I shut it down and popped the hood to see if anything looked out of place- my air filter had somehow fallen off of my cold air intake. I put it back on. I checked everything else out and everything seemed OK. I fired the car back up and got it into the garage- seemed OK.

I haven't had time to take it out (and with the rain tonight, I probably won't). It is idling OK now. I checked vacuum and spark and they're normal. Fuel pressure is reading normal as well.

Could an air filter off cause major issues? I wouldn't have expected it to (since the MAF and IAT were in place normally with no air entering beyond either). Could my air filter being off have caused my problems?

Feedback appreciated.

[TJH64]

You are describing a problem that I was experiencing, also in my 95. Ran OK upon initial start, then would deteriorate as it reached normal operating temps, missing, running way rich. Car would stall, very, very hard starting and when it would start, it sounded like pro stock car, tons of black, fuel rich exhaust.

Make a long story short, replaced the ignition module, no difference, replaced the stator in the distributor, no luck. I did some research, decided to replace the Engine Coolant Temp (ECT) sensor. BINGO!!

This sensor is located on the front, pass side of the intake and reads the coolant temp and adjusts the fuel accordingly, thus the symptoms as described when it goes bad. I bought the brass one from Autozone which was $45 and took about 10 minutes to install:goodidea:

Hope this helps, let us know.

TJ

[SAC81]

I just got back from a 30 minute spin (I discovered the joys of ET Streets, 4.10s, 3000 RPM stall, and damp roads :D )...

It seems to be running perfectly now. I got it up to ~200 degrees, went WOT a few times, beat on it, drove it normal...it seemed to be back to normal.

I'll take it for a longer drive one night this week and report back, but as of now, it seems good. I'm guessing the air filter falling off may have caused such a massive deviance from my normal MAF readings that the computer went apeshit? Really the only thing I can think of.

[SAC81]

An update, had the car out last night for 30 minutes and it's running like a champ.

[Rodeheaver's]

if the fan was blowing air across the exposed(no filter) mass air meter, then it would make it do some funny stuff.

[SAC81]

Makes sense...either way, it's running good now. Now I have to find a way to renew my interest in the car. Lack of budget = lack of interest.