Could it be the MAF?? Please help!!
Asked by 08GPtroubles Nov 14, 2013 at 08:54 AM about the 2008 Pontiac Grand Prix Base
Question type: Maintenance & Repair
About 5 months ago after stopping at the gas station for a soda I started the car, it was
very rough at idle, put it in reverse and the check engine light came on. It was sputtering
and shaking. I only live 2 blocks away so decided to drive it home. In a matter of seconds
the light started flashing. Next morning I took it to the part store to have them check the
codes. It was a P0300, random multiple misfire, took it to the shop they changed the
plugs wires and a PVC valve. After their little test drive the problem still wasn't fixed.
They then told me I needed to replace the catalytic converter. Not being a cheap fix it
took me about 3 or so months to get that done. Had the new cat put on at a muffler shop.
When he called to tell me it was finished he warned me that it seemed to him it was still
missing. At the part store again got the codes read, still the same, cleared the codes and
drove about one mile before the light came back on. Codes read again for it to still be the
same multiple random misfire. Sometimes at start I have to give it a little tap on the gas
for it to start. The engine light is always on solid and flashing if I go over 30mph. Gas
mileage used to be 22-24 now it's 12-13. Yesterday I started the car and it was shaking
very rough. I now have no power and the car will not go past 20 mph. I had a friend
mechanic suggest it was the mass air flow sensor or the coil packs. Any advise or
suggestions will be appreciated. Thanks in advance. Oh and there's about 160,000 miles
on it. It doesn't leak fluids or overheat.
20 Answers
08GPtroubles answered 11 years ago
Thank you for the helpful info. I had to replace the ignition module.
I'm having the same is that problem with my 2005 Pontiac Grand Prix.what exactly is the ignition module..?The coil packs?
08GPtroubles answered 10 years ago
It's the module that the coil packs sit on. You have to take the coil packs off I order to get to the ignition module. Hope this helps.
I just started to have this issue.Did you all have any luck fixing p0300?
I have a random misfire, and hesitation with my mass air flow sensor plugged in... If I unplug the MAFS the random misfire goes away.. Try this until you find your problem
Things I have changed that still didn't fix my problem MAFS three times, O2 sensors, coil packs, ignition module, IAC, TPS, catilytic converter, lower intake gasket, supercharger gasket, egr, valve cover gaskets plugs and wires, coolant temp sensor, map sensor
Try replacing alternator, the regulator is built in the alternator and they go bad. You may notice your dash lights flickering, if so. It's the alternator. I pulled mine off and had it tested, passed all test. I replaced it, fix the problem.
I'm having same issues with my grand prix, did yall find the solutions??
14michaelb answered 9 years ago
i have replaces the ignition module and all coils three times now since february..no mechanic knows why. any ideas?
08gptroubles- thank you, I replaced coil packs and module, it worked. everywhere I took the car they wanted to replace a perfectly good catalytic converter
I've got a 2000 GTP and it does the same thing periodically. Its the number 5 fuel injector that is causing my issue. A bottle of Heat and premium gas (which i try 2 always use because she prefers it for sure) usually takes care of the problem for me. Recently it was sitting for over a year so its doing again but previously i just used Heat every other Tank of gas and it prevented it from happening at all
I was having the same problem (OBDII code P0300 and P0301). I changed the battery, plugs, wires and coil packs the problem still exist. I took it to have the catalytic converter changed out and the tech told me he would do it but in his experience the problem was something else. I decided to wait on the catalytic converter and try a few more things first. When I read this post I saw that the ICM (Ignition Control Module) solved another's situation I decided to try it as well and it was indeed my problem. Bravo and thanks for the help!!
I have a 2001 grand Prix 2001 and it has a #1 misfire I have changed the spark plugs wires and coil pack even checked the icm and also changed the cat it still misses at times not much other times the hole time I drive it I can't figure out what's going on my next guess is the fuel injector for #1 side cause my macanic said he's checked all the egnishion side and its.nothing on that side it also does this while under a load ex if I power break it HELPME PLEASE
We changed the plugs ans wire as never had been done but was able to movie coil packs around and found it to be the ignition control module not the catalytic converter! Yeah
Before spending any money check your fuel injectors one by one.....Its free.....Take the little clips off of the plugs that hold the wiring on to the injectors......start your engine......one by one unplug the injectors and see if unplugging each one makes your idle rougher if you unplug one that doesnt change the idle at all then replace that injector....if they all function properly then go to coil wires....unplug each one one at a time until u find one that doesnt cause the motor to run rougher.....when u unplug each coil plug wire you should see spark jumping to ground on coil.....if it doesnt then your coil is bad....if they all do then it is your plug wires or plugs.......low cost troubleshooting.....
honey_do_man answered 5 years ago
If you are going to check spark,use a spark gap tester.If you force the spark to jump too far or ground to random electronics you can fry the module or a coil.upper plenum gaskets are a known flaw on pontiac v6. Have seen vacuum leak at the end of a runner lean out a cylinder to the point of misfire.As the engine heats and cools different cylinders leak and run lean.
WTF? Are these cars pieces of shit, or WHAT? I have an early 70s pickup truck that doesn't even BEGIN to have anywhere NEAR this number of nightmares going on. FYI, my car is a 1999 Pontiac Grand Prix GT with (you guessed it) 'multiple misfires. Have so far replaced: Plugs Wires Coil Packs Vacuum 'harness' (evap system) Fuel Filter Fuel Pump If this STUPID SHIT keep up, the next thing I'm going to replace is THE CAR. Fucking stupidity. Pontiac SHOULD have gone under. If you can't build a reliable car, just fucking admit it, shut your damned doors and stop wasting MY time AND money..
honey_do_man answered 5 years ago
GuruN82T8 I completely understand your aggravation. But you have a 20 year old car that apparently had good plugs,wires,coil packs,vacuum harness,evap system,fuel filter and pump.That all shows the car is good but the diagnosis was bad.Throwing parts at a car almost never works and all those parts could have been tested first. All that dose is waste time, money and raise blood pressure.If it is on certain cylinders look at what controls only those.(spark plug,injector,compression)Is it random on all 6? what controls all 6? (map,o2,throttel sensor)Different sensors used cold and hot( open/closed loop).Every time you start it or random(bad ground,loose sensor plug is vary common on GP).Test everything you can to eliminate everything that is not the problem first.
I have 2008 Grand Prix. Error code P0300 random misfire. 117200 miles on the car. I figured it just needed a tune up I changed plugs, wires and coil packs. Still had a random misfire. I did find a plug wire that was worn through from vibration to the core. It looks like the plastic engine cover must have been sitting on top of the number 2 cylinder wire. Then I changed the ignition control module. Problem is gone. Wonder if the bare number 2 wire damaged the ICM.
If u unplug the cam, crank,and the ignition coil wire, and completley take it out. Now take all of the trappings off and look at every wire. Now u will notice that there will be one or more wires exposed, separate them and tape them up one by one and re install the harness then u will have full power again.
