Trannyman

Ok, here's a problem I've been having for the past couple of weeks. When cold, the car runs like a champ. I can flog her and she screams for more. But, once she gets hot, I get an intermitent miss/stumble at rpm's over 2500 rpm under load. MAF has been cleaned. IAC has been replaced. TPS set to .98v and sweeps smoothly to WOT. Timing is set @ 12*. Has new plugs/cap/rotor. No MIL illuminated (yes it works). Only Thermacter Air Codes present (44/94).

The miss or stumble is erratic, what I mean by that, is that it's not like a dropped cylinder and I can see the RPM guage moving in sync with the miss/stumble. I have access to a MODIS scan tool. Should I start scopin' the TFI module when it does this?

I also found some data on a recall for distributors equiped with a black stator that they were to be replaced with a white stator. So I removed the distributor cap and sure enough I have the black stator. Am I lookin in the right area?

The engine is bone stock and has had the salt & pepper connector recall done.

**EDIT**
I should add that the fuel pressure is dead on for stock. Checked at 40lbs.

91hatchgt

How many miles.. I am just over 120,000 miles and I have the same kind of stumble after about 3k RPM's... I found out that my stumble is worn valve springs.. It causes everything to become out of sync and can be disasterous for your valves.. Check those out, as you may have the same problem, it may be mechanical, not electronic.

SaleenSpeed

Wouldn't your compressino be bad if you had messed up valves?

stanglx2002

does the stator look worped at all bc if it is then it needs to be replaced i think u are on the right track

birdman076

I had the same problem on mine a while back, ran good till it warmed up and then it had a miss that would get worse every time I drove it. Mine ended up being the ECT sensor, its on the passenger side front of the motor in the black tube that runs to the heater core. Unplug it and see if the car runs better after warmed up. It will give you a check engine light when its unplugged, but the ECM gives it a default reading so you can isolate if thats causing the problem or not.

Trannyman

I'll give that one a try tomorrow.

I had enough time at work today to hook the MODIS up and scoped the crank position (pin #1 on the TFI) and had a beautiful wave form all the way up the rpm range. Then did a frequency check and no drop outs or glitches all the way up rpm range. Next I checked the SPOUT (pin #2 on the TFI) here I also had a beautiful wave form all the way through the rpm range. Also had no drop outs or glitches in a frequency test. I had the engine warm enough that it was stumbling at 3000 rpm and up today during the tests. But as I said, it was giving beautiful wave forms.

Trannyman

I haven't been able to look that closely at the stator, the reason being that the strut brace runs right over top of my distributor. Bit of a hassel, but it's just nuts and bolts. I'm going to try to get the keys to the shop for Saturday and do some more indepth looks. I'm also going to change my rear main seal (bad leak) and probably gut the cats while the H-pipe is out.