Another thought.... even though the coil pack checks out with an ohmmeter, could it be cutting out under a load and causing the stuttering/backfiring, etc. that I am seeing? Also, even with a new MAF sensor, it is giving me a 157 code in continuous memory.
Anybody got any more ideas???
I suppose it's possible the coil could have an intermittent failure.
On the MAF, if it's still showing a problem, with a new sensor, maybe it's a problem with a wire? Check all the wires form/to the maf. Look very carefully for any cuts/breaks.
I haven't changed the injectors, but I have used a mechanic's stethoscope to listen to them as they fire, and they all seem to fire right. They are also within tolerance levels as far as resistance is concerned. I also did a compression check, and all turned out well. I really just don't know what else to do with it! Would the camshaft position sensor cause any of my problems? The odd thing is, when it is in park or neutral I can "romp" the gas and it jumps right up like it's supposed to, but when I am driving, it wants to bog and chug unless I just barely press on the gas, sputtering and trying to backfire if I really "get on it". (frustrated)
So, the problem only appears under load? Idles fine too (smooth, steady)?
Also still seems to be using WAY too much gas! But still no codes!?!?!?!?! Seems like a problem that is this bad would be throwing a code or two, but nothing!
Is there any connection between temperature/run time and the problem? I mean will it run fine when cold, then have problems after it warms up? Is it the opposite, runs bad when cold, gets better when hot? Or is there no connection? If there is any connection between the problem and temperature/run time, take a good look at the coolant temp sensor. Some vehicles have 2. One for the gauge, and a seperate one for the ecm. If the ecm is getting incorrect temp info, it can cause all kinds of problems. If the ecm still thinks the engine is cold, when it is not, you will have a very rich mixture, which could send unburnt fuel into the cat, causing it to burn inth cat, and the cat to glow. Conversely, if the engine is colder than the ecm thinks, it won't get enoug fuel, and it will stumlbe/misfire-especially under load. You need to get a scanner on the vehicle and monitor the coolant temp ( or what the ecm thinks it is) and compare to actual temps (with a thermometer of some kind). It would be best to watch it from stone cold (after sitting overnight, through complete warmup)
Ok, I reeeaaaaally hate to throw any more money into this thing, but I think I'm gonna head out to buy a crankshaft position sensor, a camshaft position sensor (I do have one on the 94, right?), and maybe a new EGR valve solenoid and DPFE sensor, even though it's not throwing any codes at all, now! Boy, am I getting sick of this! If anybody has anything else to add, chime in, by all means!
Simply throwing random parts at it is a good way to waste a lot of money. Yes, sometimes parts can fail, without throwing a code, but you should try to test a suspect part, before just replacing it. If you don't even know if you have a camshaft position sensor, then you shouldn't be trying to randomly replace it. Also, you can easily test the function of both the egr valve and the dpfe, using a hand vacum pump. Try looking it up in Haynes manual, try a google search ro search the forum for "egr testing" and/or "dpfe testing". You could also get a subscription to
www.alldatadiy.com It's the same repair info shops use. It's only $25 a year, for the first vehicle. They give you big break on subsequent vehicles.
If you can rev the vehicle up ,in nuetral, and it idles, with out a problem, then the crank/cam shaft sensors are not likely to be the problem. Neither of these are "load-based" sensors. They are "rpm-based".
Maybe I missed it, but have you actually disconnected the cats? Cut the pipe if you have to; you can use a $3 coupler and welder (or exhaust clamps) to put it back together. It really sounds like they might be clogged.
Contrary to my, don't just replace it lecture, O2 sensors are a wer itme, and if you know they haven't been replaced in a long time, you could go ahead a try new ones, as they are probably due anyway. A bad O2 sensor can definitely hurt fuel economy, but I've never seen on bad enough to make the cats glow.
Like I said, stop throwing random parts at it, slow down, and think. Take the time to do a little research, and I'll bet you'll find clues that will lead to the answer.
