joecutlass Posted May 23, 2011 Report Posted May 23, 2011 so todays trip to the u pull it was the longest the gp has been since ive pruchased it. about 120 miles both ways. i noticed the car was idling a little odd and seem to be misfiring at a driving speed of 55 to 60 mph. first thing i thought was spark. the plugs i had in were a little worn out so i replaced them from acdelco to bosch platinum +4. the wires were installed when i bought the car with a new icm and three new coils. ive got spark. without a doubt. does anyone think this could be a potential transmission issue? Quote
tornado_735 Posted May 23, 2011 Report Posted May 23, 2011 First things first: get those Bosch plugs out of there. Our DIS' do not like them. Quote
joecutlass Posted May 23, 2011 Author Report Posted May 23, 2011 ive been running boschs in my cutlass for about a year now and they are phenomenal. what do they do to the dis system? Quote
3pt1lumina Posted May 23, 2011 Report Posted May 23, 2011 I had Bosch plugs in the 97 for about 3k then I started having misfiring issues and car ran funny all the time. Took them out and replaced with ACDelcos runs like a champ again. Quote
AL Posted May 23, 2011 Report Posted May 23, 2011 My 91 wouldnt even start with Bosch plugs, Put ACDelcos in and it ran perfect Quote
tornado_735 Posted May 23, 2011 Report Posted May 23, 2011 I've never run Bosch plugs, but the first time I mentioned something about putting a set in, no less than 5 people here told me to not even bother. Quote
19Cutlass94 Posted May 23, 2011 Report Posted May 23, 2011 Your essentially putting a ford part in a GM car. These dont mix well. Stick with AC's. Quote
joecutlass Posted May 23, 2011 Author Report Posted May 23, 2011 Ok. Delcos are back in. Same issue. Sputters between 53 and 59 to be exact.... Quote
Crazy K Posted May 28, 2011 Report Posted May 28, 2011 year/make/model? 3100 car(or cars with the coils on top) often do not suffer the heat cycle wear and tear that cars like a 3.1 or 91-95 LQ1 suffer, whose coil pack are next to the front exhaust manifold. Bosch plugs are bad, bosch +4 are far worse!!!! we tried those in my dad's old Subaru and they needed replacement in 300 miles from fouling out. Presumably the multiple electrodes result in fouling because as the spark jumps around the electrodes and do not get defouled from full time use. a good way to check for coil/icm condition is a spare plug wire with a screwdriver inserted in the end and the engine cranked to check for spark with it attached to each point on the coils in turn. All 6 should have a consistent spark. next after that test... you could do the same with each existing wire to see if any of them are weak or bad... Quote
joecutlass Posted May 28, 2011 Author Report Posted May 28, 2011 Problem solved. It was the icm. Quote
urbex Posted May 29, 2011 Report Posted May 29, 2011 I figure if GM wants to put it in the car from factory, it has to be alright. But then my theory blew when I bought my HHR... Quote
joeld Posted May 30, 2011 Report Posted May 30, 2011 Problem solved. It was the icm. In your first post you wrote the ICM had been changed. Was this a new ICM that was bad? Reason I ask is I just installed a BWD new ICM trying to cure a somewhat low and rough idle on my 95 GP 3100. Thanks Joel Quote
joecutlass Posted May 31, 2011 Author Report Posted May 31, 2011 It was a bwd, good thing it has a one year replacement. I put the origional back in. There was nothing wrong with that one. I just had that new one so i threw it in with the three new coils i had when i bought the car.. Quote
joecutlass Posted May 31, 2011 Author Report Posted May 31, 2011 Rough idle. Had the same issue with my gp. Check the tps? Quote
urbex Posted May 31, 2011 Report Posted May 31, 2011 MAP sensor could be too, but I'd check first with the TPS. According to a TSB from GM, the MAF could also be the culprit. Quote
joeld Posted May 31, 2011 Report Posted May 31, 2011 Yea, I've checked the TPS, installed a new IAC valve, all 3 coils are new, new ICM, different injectors, new cam position sensor, new crank position sensor(in rear of block), new AC standard plugs and wires. I really hate to admit how much I have changed! Scanner shows proper voltage at MAF, both with key on engine off, and with engine running. Vacuum gage reads a steady 17in. at idle Engine has always had a good smooth idle at approx 750 rpm, now it is about 650 rpm. Just enough to feel a little rough. Thanks Joel Quote
joecutlass Posted May 31, 2011 Author Report Posted May 31, 2011 Fuel pressure? Could be a weak pump, clogged filter, or bad fuel pressure regulator. Quote
joeld Posted May 31, 2011 Report Posted May 31, 2011 Forgot to include a new fuel filter, checked pressure and it instantly goes to 41 lbs with key on. Holds pressure good. Engine running pressure is 38 lbs. No evidence of fuel in vacuum line at regulator. Joel Quote
joecutlass Posted May 31, 2011 Author Report Posted May 31, 2011 Your pressure is fine. Could be bad spark plugs. Check for gap? What plugs are you running? Those boschs were horrible. I put the delcos that were in back in and it ran fine. Then i out in delco platinums and it runs beautifully Quote
joeld Posted May 31, 2011 Report Posted May 31, 2011 New AC Delco plugs #R44LTSM6 and wires. Joel Quote
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