The '92 Park Avenue Ultra Acceleration Blues

There are probably a few variations on this one, but I've been working through my current problem and I could use a fresh look at what I might try next.

So here's the situation...my '92 PAU engine stumbles or misfires on hard acceleration at higher speeds. It got about 235k miles on it now.

Let's say I'm doing 55 mph and the engine is turning over at about 1500 rpm. I got to pass someone or go up a hill, basically floor and then the engine starts cutting out or missing and it's pretty bad. I seem to be able to take off from a dead stop and accelerate well with no hint of problems. The idle is a little rough.

So far I have replaced the catalyitic converter and fuel filter. The spark plugs, spark plug wires and o2 sensor are all new ACDelco. I've replaced the filter and cleaned the MAF and throttle body. I've checked the coil towers and found they are within the proper resistance values. There are no codes set in the ECU.

The fuel pressure checked OK at idle and vacuum looks very good. I haven't tested compression is a while. I've run a couple of bottle of Heat through the gas tank to remove any water. I think I'm past all the obvious stuff. I don't have a scanner to read any live engine data and I think that might help. I think the supercharger is OK and I can feel boost.

I read some things about the ignition control module, the one the coil towers sit on as a possiblity.

What do you think might be causing the trouble? Thanks for the help!!

What octane fuel do you use? Have you ever changed the crank position sensor? Have you checked the cam gear magnet, or the cam position sensor?

I always use high octane, 92, right? I haven't checked those other sensors, I'll start looking into it. Thanks!

92-93 octane is correct for the S/C engine. If you have access to a scanner, look at the MAF & EGR functions, this test could indicate an unmeasured air flow problem.

I'm looking into a computer based scanner. I have a good electronics background so building the ALDL cable is pretty straight forward. But, I'm not sure which software will read the L67 SC engine properly.

Anyone with any experience in this area that you know of? I've always wanted to find a Tech1 on ebay that I could get for under $100, but I got disenchanted pretty early on. Lately more people are offering cable/software combinations that I could install on a laptop. I just want to get one that works.

If that doesn't work out, what scanner should I set my sights on? There's an Actron that reads OBD1 and maybe even an older one that I could get used for a reasonable priice. It's the live data I need, but I just don't want to spend a lot. But, I may have to bite the bullet.

Again, thanks!

CLICK HERE (http://www.aldlcable.com/)

Thanks for the reply. Yes, I've looked through the list and it seems like one just has to really just jump in and give it a try. There doesn't seems to be one package that fits exactly, but you have to admire those who put in the work to extract the basic data and provide the programs!
That said, I guess I'm leaning towards picking up an Actron off Ebay....you can't beat the packaging. Thankfully, the car is running pretty good and I can tinker around checking parts of the system.

Did I read correctly in another thread that ignition modules can be checked at Autozone? I'll have to give them a call.

If you find out what causes this please post it as mine does the same thing so I just avoid punching it at hiway speeds. A slight bit of pedal makes the spedometer climb pretty fast. It's new to me with 105k (a new supercharger cause no one ever checked the oil even tho if you ran a finger underside of the snout a leak was easily felt/seen and the case was dry) new harmonic balancer, no codes and runs perfect otherwise. You should be able to do all your diagnostics and programing through your climate control with the aid of a manual, I thought.

You should be able to do all your diagnostics and programing through your climate control with the aid of a manual, I thought.
This method will only show DTC's (codes) set, no live data. :shakehead

I built a simple two transistor interface for the RS232 connector on my laptop. The results so far were not that great. Hmmm, maybe I should get that Actron........

The interface circuit is a cute little level shifter that I found on the ALDLCable.com web site. There are more elaborate ones that utilize the MAX232 chip, but I just wanted to get my feet wet. The interface works but coupling it with software is the challenge, duh!

So far I've tried EFILive, Freescan and GMECM. Nothing is working. I'm pretty sure the data is moving but I'm either not sending stuff back up the line or the frames of data don't capture properly and I get zilch.

EFILive is probably the best of the bunch so far.

Thank heaven for U-Pull-It. (the rest of the story is a little long winded, but hang in there)

Well, I feel pretty good about this one. Today I got down to the local U-Pull-It (UPI) and saw fresh meat, a '90 PA, right there in the front row. It still had the ignition control module (ICM) and coils packs. So I got out the wrenches and did what comes naturally. I also got the MAF sensor.

I wandered around a little more and spotted a '92 Riviera that had a the ICM and one coil pack. Between the two model years they are really just about the same unit, but I had to go with the Riviera's unit just becase it looked to be in a little better shape and matched the year of my PAU.

The costs were reasonable, I think. The coil packs were $12, the ICM $14 and the MAF was $12.

I get home and clean up the MAF and sprayed it down with some CRC MAF cleaner and install it. I got my coil pack off and installed the replacement ICM and replaced one of the coil packs with the UPI coil.

While putting the original coil packs back on the ICM I see they both have hairline cracks running top to bottom. EUREKA!!! This could be the problem, ya think?

I think the cracks might have let in some dust and moisture and started failing under heavy load such as flooring the accelerator while passing or going up a hill.

So, I drive back to UPI for more coil packs. Now, on the way there I still had misfires under load, but I really felt those cracks in the coils were the smoking gun or guns, so to speak.

I wound up getting two packs. One from the '90 PA and the other from a Oldsmobile Cutlass Cierra (sp.) wagon that had aftermarket coil packs (and Carquest spark plug wires) dated 2006. The after market coils looked exactly like the PA's I thought I might as well take the chance. The engine in that car was a 3300 that looked exactly like my 3800. When I got home I checked resistances and they matched the originals.

After installing three sealed packs I took a test drive. NO MISFIRES!! The engine now handles the load probably the way it was intended. The car doesn't burn rubber and press you back in your seat, but the engine doesn't stumble or misfire either.

Can you tell I'm excited! As always, it's going to need some more driving to validate the repair. What a relief; I hope my experience helps.