pichinco

All right guys, here's a puzzler for you. I thought I had it licked but it's back.

I bought this '96 GT back in November. At higher RPM's (especially 3rd gear) I got some detonation/valve rattle. I decided the doctor who owned it before probably ran it in town a lot and never got into so I had carborn build up. Several bottles of fuel injector cleaner helped, but still had the problem. Read if you disconnected the MAF and the problem went away, it was probably the MAF. Replaced it. Helped for a while.

Now it's back. There is also a miss when you load the engine. i.e. accelerate while below 1500 rpm's. All this only happens after it gets warm. Which is the reason I really thought it was the MAF. Running too lean after it got warm.

Any ideas? I'm stumped.

One other question. Where does your temp gauge generally run? Wondering if I'm running too hot. Never seen/heard the fan come on unless using A/C.

vfast

well I would scans for codes at this point and check the 02 sensors...you can pull them and clean'em..sometimes it works...another thing could be a valve or spring problem. but not likely....try puting some water/achol mix into the intake track to lossen up the carbon on the pistons. timing could be the issue as well as in a wore timing chain

pichinco

You can get codes w/o the engine light coming on? Now there's some info...

Never thought about the O2 sensors... What do you clean 'em with.

Worn timing chain....at 83,000 miles? That would suck.

Thanks for the input. Gives me some more stuff to look at.

N2OJunkie

yes you can pull codes early before is too late ... i.e. when the light comes out..

96mustanggt46

my car was slugish on acceleration and the engine light did not come on and i wanted it to so i could have it checked and it finaly did and cylinder 4 had a couple missfires. So i turned out the lights in the garage at night and looked under the hood and saw a little spark frome the #4 wire and took it off and there was a crack in it so i got new ones and runs good now. so i would check wires for another sign good luck you will figure it out!

96mustanggt46

O and this happend at low rpm's too.

pichinco

I think I know what you guys mean by early. Correct me if I'm wrong, but you only get the engine light if the error occurs on three consecutive engine starts. I assumed that meant the code wasn't stored until then either. Are the codes stored on any and every error?

Another question...vfast mentioned O2 sensors. Would that cause the situation I'm describing?

The H20/alcohol mix into the intake. What conentration and how do you get it into the intake? On my old 64 1/2 I'd pull the breather and spray it into the throttle body...a little harder to do now. I've heard folks pulling the hose to the PCV valve and "spraying" it there with a water bottle.

pichinco

Took your post to heart and decided I'd never looked at the plugs. Pulled a couple...gapped at ~.035 and pretty worn. New Autolite Double Platinums and a new set of wires... WOW!! So that's what it supposed to run like? Thanks!!