I'm at a freakin' loss here.

[Blank-Disk]

For months now, my 93 ATX has been giving me trouble with power, and incesant jerking while stopped. It's obviously something going wrong in the engine. I'm saying that it's a cylindar missing and sometimes just dropping dead. It's frustrating as ****, and I'm at the end of my rope. I've run codes over and over with all 111's and 9's, I've cleaned every ignition part I can find, and replaced the CID, and nothing. After a comptuer reset, it gets better, but then progressivly becomes worse than before, faster than before. Most of the time I'm running at what feels like 100hp, and the car will NOT STOP SHAKING when stopped, no matter what the tranny is set to. I've turned this site inside out looking for similar cases, but nothing is exactly right, and when I try the fixes they used, it never works. Is there some thing, some where, that the ECC test wouldn't see, that would cause this? It seems like the car runs perfectly when the test is going, but sometimes the car DOES start shaking while the test is going, but it'll still give me 111. What the **** is wrong with my car?!

 

[oh_SHO]

We need more details of what you have done to the car, etc... Like plugs & wires, oil in the wells. I am sure you have covered these things but we need to know what've done so we can build from there.

 

[Blank-Disk]

you're right, sorry about that.

The plugs and wires are all good, all under 2 years old. I pulled them all out in June when I did the 60k (including valve cover gaskets and plug seals) and everything looked great. There's still no sign of oil in the plug wells, so that's covered. I cleaned out the MAF and TPS, as well as their connectors, adn the connectors on the CID and DIS. I replaced the CID, which helped slightly, but didn't eliminate the problem. The transmission was rebuilt the same tiem as teh 60k, and is still doing fine (the car has about 85k miles).

I ran the cyl Balance test, and it came back fine. The engine did everyhting that it should have during the test, so bad plugs are pretty much out.

I noticed that when it's hesitating badly, and I punch the gas, it'll take it's sweet time moving. Secondaries open, the engine is roaring, and the RPM's are consistent with the mph, but it's taking it's SWEET time. Sometimes though, it'll get tiny jolts of boost, like everything goes back to normal for a split second. Sometimes it'll accel like a rocket, as it should do normally, and then go right back to put-putting around. So the problem is quite random, and like I said, it gets better when I reset the comptuer, but quickly goes right back to bad. I've raised theories that the DIS may be the problem, but it's SO expensive to replace, I'd much rather troubleshoot this one than do trial and error with new parts. I've also considered the coil pack, btu I don't knwo enough about it to determine if it's teh cause. Any input is appreciated.

 

[shofun93]

My first thoughts are a possible bad fuel filter or a problem with the injectors. The injectors are possibly clogged and causing the problems. I would replace the fuel filter and check it reguardless. I do mine about every 30K.

GL, Jason

 

[oh_SHO]

I agree, have the fuel pressure checked. It almost sounds like a clogged cat but if the problem is intermittant then I would doubt them being the problem.

 

[Blank-Disk]

Oops, forgot to write that one up. I replaced the fuel filter about a month ago. I also checked the pressure and it was perfect. I have considered the injectors, but my milage is actually pretty low, about 18mpg, so clogged injectors wouldn't be the cause of that. If anything they're letting too much through.

 

[shofun93]

did the problem start before or after the fuel filter change? Could be some contaminents got through when you changed the filter.

 

[Blank-Disk]

the problem started long before the filter change. It was an attempt at a solution when i thought it was teh fuel pump (which it's not, made sure of it).

again, teh codes check OK, so the problem isn't getting picked up by the computer.

 

[SHOtimer]

The fuel pump might be pumping inconsistant pressure. Also, I would try unplugging your MAF and seeing how the motor performs like that. If it gets better and isn't sluggish your MAF is bad.

Are you running any chips/LPMs or mods?

Doug

 

[Blank-Disk]

I checked the fuel pressure (even bought a new pressure tester) and it's perfect. I couldn't pray for better results. I'll go out right this minute and do teh MAF test, I'll post in about 10 minutes.

 

[Blank-Disk]

okay, just disconnected the MAF, and got some interesting results. I started the car, and it began freaking out, and the RPMs dropped to about 500 (WAY lower than usual). Then I took off, and went up on a good straight road and took it to 40mph. It seemed to have it's power back, but was still missing a bit. Also, wehn i revved teh engine, it still did the skip-a-beat sounds, which i'm sure are misses. So what does this indicate?

 

[SHOtimer]

Well, without a MAF signal your car has no idea how much air is coming into the motor because it cannot meter it. But, if the MAF is bad and it is metering it uncorrectly then it will make your car run butt slow. The low idle is a result of having it disconnected. My thought is that you need a new MAF. Have you tried to 'clean' it? If not I would try that. Also before dropping $ on a new one, I would try testing a known good one from a SHO owner around you. It would take a matter of minutes to swap and see if a known good MAF takes care of your problems. Sounds like we made some progress here...

Doug

 

[95SHOdude]

Another idea to try

When I was having a simular problem it turned out to be the IAB. I bought a used one on line and the problem got worse so I broke down and got a brand new one. Problem fixed. I'd send mine for you to try but I sold it already. Something to try if the MAF does pan out. The IAB was the last thing I replace due to the cost of a new one.