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Engine chuggin

D

dewski

New member
Well I having a problem with my car.

Sometimes my car will start chugging, the rpms will start bouncing up and down from 1500-600 or so. It never happens when I'm stopped, parked, or keeping a constant speed. It happens when I let off the gas and start coasting or slowing down. I recently had a tune up on the car, spark plugs, wires, I also have done a tranny flush. I need some help please.

Thanks Mike
 


Well based on the info you are giving, my first thought would be possibly the MAF. Maybe it needs to be cleaned. Could also be the fuel filter, though that I believe would cause the issue at any speed rather than the ones you describe. Could also be an EGR issue, it may need to be cleaned or is failing. There are several things that could be suspect though.

Are you getting a check engine light or anything like that.

Also, though not an apples to apples comparison, the '89 Grand Prix I had did this same thing and it turned out to be the crankshaft position sensor, but the symptoms you are describing I have not seen associated with a crankshaft position sensor of any of the newer GP's, particularly the supercharged ones.
 
Well I changed fuel filter, and the MAF has been cleaned recently. The only code from the car is the code for a leak in the EVAP system which wouldn't be causing this. The only other thing wrong with the car is the my ABS and TC lights are on but no codes? So we thought that part of the comp was fried somehow so its not working. How would I get the EGR looked at or figure out if its not working right?
 
Well if the car is coming up with an EVAP code then I would by no means rule it out as the problem, particularly if it is trying to purge too much. ABS and Trac Light will come on and stay on if one of wheel bearing sensors goes south, which one it is you will need a scan tool capable of reading ABS codes.

As for verifying operation of the Digital EGR the GP has, Im not sure how to verify operation. I can do it on the older vacuum operated ones but the digital ones Im not sure how to test them.
 
Okay well, they cleared the code when I took it in last so they said to wait until it came back on, and they would smoke the system to find the leak and fix it. As for the ABS codes, I've scanned it and says there is no codes or anything wrong, a wheel bearing sensor would so up as a code right? Is there a separate comp(ecu) for those systems? I'll get back to you when the EVAP code is fixed and see if that was my problem all along. Thanks for all the help so far. Mike
 
Yes, the ABS codes are stored in the BCM (Body Control Module) and your standard automotive scanners will not read it. You need a scanner specifically for reading ABS codes.
 


Hey there Mike, Sounds like a sensor if you ask me. Most likely the MAF or MAP. Try running a diagnostic and see what the reading shows (that's if your mechanic has not already done so).

Good luck.

Regards
 
The surging is caused by an aftermarket cam :p J/K

It still sounds like a MAF to me. A buddy's GTP did this when we installed his rockers and we swapped MAF's to see and sure enough...I'd swap it out and see ;)
 
Thats is what happened to my car. Why it didn't make it to the Branson meet.
It was the 1-3 Coil Pack. O'Reilly $20
Everyone told me MAF too, but it wasn't.
 


Hey thanks for the replies, are there any links or how-tos on checking the MAF and checking the coil packs? Mike
 
Ha, I have the same problem, except mine came after switching to MSD spark wires... I changed back to Stock plugs now. No service engine light or nothing, but it's definetly missing big time. Now its at the Dealer and I'm about to get F'd in the A in cost. just great :th_shakinghead1::mad::th_sign-ripped::th_beer-smash:
 
Well i feel really Fn dumb. It ended up being a messed up plug wire- I changed to MSD's and must have somehow misdone one of them in the back, and so I then switched back to stocks, but it made no difference because I already had screwed up the order so it was missing big time. Now $200 later, I guess it was a good thing I brought it in cause I'm having the ABS/Tire press lights fixed and the recalls are getting done- So thats the good end of the deal, the bad part is I probably spent $100-$150 in them diagnosing the plug wire malfunction. I JUST GOT SERVED...:th_wtf: :th_angry-pissed:
 
and now i get to drop around another $600 amount due to the fact that the backside of the intake was leaking anti-freeze, and eventually with the colder temp approaching, it would crack completely and drop into the cylinders, so it's a good thing i caught it now rather then later, cause it would have been done for. In response to whoever said that synthetic is not worth running in our cars because they are "3k cars", I totally disagree because of the fact that my car has over 1.5gs in just the motor and struts (no performance in this). So I think it depends on your views and what you think your car is worth- for example I am going to run synthetic because I want the motor to run as long as possible (at least for right now) because I would rather stick money into looks and performance then into fixing, as I also have to be saving for school - just my opinion:D
 
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