97 GTP Engine woes

Okay, I'm at whits end and I don't know where to go from here. I have a very strange problem with my GTP and can't figure out a fix.

When the car starts, it runs well. However, while driving I have...problems. Sometimes it is nothing more than the tach shutting off, other times the tach will shut off and this is accompanied by a stuttering of the engine, but the engine stays running. Still other times the engine shuts off completely. Usually when this happens, as soon as I get to the side of the road it will refire but not always.

Which brings me to my next problem. Sometimes, heck about half the time, the car will not start. This is even more pronounced after the car has been driven. The problem started very mildly (with just the tach issue every now and then) and has become progressively worse to the point where I'm saying a little prayer before turning the key over.

This is the work history on the car. I got it with just under 70K on it. I now have 117K on it. I've changed out the intake with an in fender system. The pulley has been upgraded to a 3.25" pulley. When I did the pulley upgrade the first belt I had began to come appart. It did so by having part of it begin to seperate (though not completely) and this piece thrashed about inside the engine compartment for a while before I could get over, shut the engine down, and remove the shredded piece. (This happened before I started having these issues). Once these issues started, I did the following: Changed plugs (running Autolite 104 plat.), changed wires, changed all three coils, and changed CPU (upgraded it as well. :D). Problem still persists.

Also of note, the SES Light SOMETIMES comes on with this, sometimes not. Also the engine seems to sputter and miss at WOT also causing the SES light to come on. This problem of sputtering at WOT had started after I did the pulley/plug change but before everything else.

This is where I'm stuck at. Where to from here? I've seen posts here about crank and cam shaft sensor replacement as well as the fuel pump module. Could these be the culpret? My feeling is that it is in the ignition module. Sometimes when the engine doesn't start if I go over and press on the coils (Like I'm giving them CPR which it does, ironicly, feel like sometimes) the engine will fire back up. The other thing that leads me to believe that the problem is in this area is because that module is in the same area that was slapped around by the SC belt when it started to shred. In addition, there are times now when I'm trying to start it when it seems like maybe 2 cylindars are firing but not the rest (the engine is turning over and it feels very rough like a couple of cylindars ar trying to firing) again leading me to feel it is in the ignition module.

So there is my problem. I am quite perplexed. Any an all input on this would be greatly appriceated as well as how difficult any proposed fix would be (as in where to find the parts and can I do this in a regular household garage with basic tools or should I take it to a mechanic).

Thank you all for helping me out...for 6 months I've been trying to track this down with little luck.

Well based on what you are saying you have an ingnition problem. I just learned from Ripn12s that based on the pulley size is the spark plug GAP. What is your GAP? .55? If is bigger than this then Misses could happen because the added PSI would blow off the spark at the plug. Also if you replaced the Coil Packs and cables and then sometimes you do not get fire on at least 4 cyls could be a ignition module issue. Electronic parts can fail intermetently and be a headech. Remember the Tach would read data from the ignition module like old cars that the tack would read from the distributor. Replace the module and check the spark plug GAPS and let us know what happens

Take the car to autozone and have them scan it. There should be codes stored for that SES light.

If u are running a 3.25 w/ only an intake as your supporting mod, then that is your biggest problem

I'd pull all the plugs again and see what they look like.

Also what PCM are u running??

I would also do this mod and see if it fixes anything

http://rmcgp.clubgp.com/fpresistor.html

http://www.pfyc.com/store/merchant.mv?Screen=PROD&Store_Code=PFYC&Product_Code=WB3006&Product_Count=40&Category_Code=GPUNDER

The resistor will fail or not but would work halfway?

I also have removed the U-bend in the exhaust but have not done a complete cat back system yet. With the pulley I have, what other mods would you suggest. Next on the list is a set of headers mainly because my rear exhaust manifold has a crack in it. Looking to go with a TOG header system but don't know what it would cost to have them installed.

I took it to a local shop and they found the Crankshaft Sensor is bad. That is getting replaced today. I'll see if that solves this problem and go from there. The PCM is a DHP module.

When my crank shaft position sensor went south, my tach shut from time to time.

Which is exactly what mine did. I got the car back yesterday afternoon and everything seems good so far. No problems all last night or this morning. We'll see how it goes. I don't qualify it a sucess until it goes a few days without a recurance. LOL

Now, the only problem that I still have is a bit of a miss or surge at WOT under heavy load...(Say...accelerating from 70 - 100). It is very subtle, not even enough to set off the SES light, but it is definately there. It is not a smooth, consistant miss like one cylinder is consistantly missing but more of a sporatic miss (cloged injectors or the above mentioned "gap issue" with the plugs???). But when I'm accelerating from a dead stop or just regular driving it isn't noticable. Any suggestions?

Well I just got the car back with the new engine in. Still on the 600 miles break in period but the smaller gap helps me at start. Will drive at least 100 miles with the scanner on to see what actually is going on