99 grand am running rough

[Aki334]

just to comment on coil packs that start with "D" - I was not very impressed (vorse than my old ones my suggestion measure your secondary and primary resistance for all coils that you have compare them to specs or go to store that has coil packs that start with original "D" measure them and compare. in short buy original (my new coil non original one was worse by 3000 ohms for the secondary resistance). good luck.

[Ian Szgatti]

I hate to send this into nomans land, but what is the possibility that this is a timing type of issue... a four cylinder? Does this motor have a timing chain or a timing belt??? I really cant wait to hear the outcome of this one.

[xeroinfinity]

Hey Ian,
It is possible but not likly.

I've seen 99's (4cyl) w/175k miles and no sign of damage to the gears or chain.

I still think its fuel related not fire .....

[Ian Szgatti]

Originally Posted by xeroinfinity

Hey Ian,
It is possible but not likly.

I've seen 99's (4cyl) w/175k miles and no sign of damage to the gears or chain.

I still think its fuel related not fire .....

whoa... I think we've been missing the boat here. I had to read the original post again to re-think this from your position... and the edited original says the problem was fixed by a remanufactured PCM. The problem was in the fuel managment system though, so you were accurate i guess. Ok, well this thread is now dead.

[xeroinfinity]

I hadnt even read his 12/26 update/edit part.....
This has happend to many 99+ GA owners(stumped me too a few times) and the shops just run you round and round till youre broke

[Aki334]

OK BREAKING NEWS HERE FINALY!!! sorry Xeroinfinity for this caps I had to use them this time because people need to see this one it will probably help them solve the similar problem that I had. Notice this time I said problem that I had it is out now . This 0300 code that I was chasing for a long time I mean printing all kinds of electircal diagrams, asking my ASE instructors, reading all kinds of books to solve my problem and not to mention all the unecessary parts that I changed when I was younger and unexperienced (now I see that all those sometimes expensive parts vere good ;( . But first I have to thank you Xeroinfinity for showing me the right direction at least - remember when I said "you are very close I think" (low pressure for opposite injectors #3 adn #4 on V6 3.1. YES I did what I told you I was planning to do. Here it is finally:
reminder GA was shaking (misfiring only in P and N) and mostly on #3 cyl sometimes on #4
solution:
1. engine on and in Park
2. used otc scanner to monitor all cilinders
3. noticed that #3 was misfiring
4. pinched outlet rubber fuel line after the fuel pressure regulator
5. noticed BIG difference in idle this time and all cylinders showed "0" for misfiring. In conclusion specs say: fuel pressure is ok if between:41-47psi looks like it was not enough for my GA 3.1 or the fuel pump filter bag is very dirty. So who ever has this problem try this before changing your O2 sensors, cleaning throtile bodies, cleaning injectors, fuel filters pcv valves, coil packs, spark plug wires etc........ Thanks onece again. And Happy New Year from Aki