won't start!!

[98 gmc]

I have a 98 GMC with a 5.7. My son drove it to college and when he left, it just died. I had it towed to a local shop, and they told me it has the correct fuel pressure, spark, compression,and the timing at TDC is right, but it will not fire. My son told me that when he put it in gear to leave, the rpm's went up, so he put it back into park, then put it back into gear, and it just quit. Any ideas?

[aflesch]

Any codes?

Does it sputter when it cranks?

[98 gmc]

No codes reported from shop. No sputter-getting a backfire through air intake.

[KMGZ400]

Take it to a shop that knows what they are doing and let someone properly diagnose it.

[98 gmc]

If they dont have any answer tomorrow, my only other choice is a dealer.

[aflesch]

Sounds like a crank position sensor to me. it is the sensor that tells the spark plugs when to fire. Just because you have spark doesn't mean that it is sparking at the right time (hence the backfiring through the intake)

[98 gmc]

same thought from the parts store. Should throw a code, I would think. Will have to purse with shop in the morning. I had a neighbor say the same thing. Hope it's that simple. Just put ATK motor in 15k ago. Thanks for the response's.

[mikejr247]

had this come into my shop accouple times and it was a distributor cap. Not saying that is your problem but that is what i look at first. Other then that with what the shop is saying it should run. Im just wondering if they checked the spark at the coil or at the plugs....