As some of you know, i have had a "really bad Miss" at various rpm's.....Well today i went to go wash and fill her up with gas when......

I push on the gas pedal even in neutral (like reving it) it misses like crazt and basically i can't even drive it now, it'll drive but just shutters and misses the whole time...I'm kinda screwed because this is my daily driver.... my wife is at church and all my spare parts are 18 miles away at my mother in laws house. anyways I am going to hitch a ride out there what parts should i bring back? I have already replaced the fuel filters, intank too, spark plug wires, i have regrounded the motor....new tps

what else could it be?

here's the parts i have availible...

alternator, cpu, coils, bac, i don't have injectors and i don't think the other fuel pump i have is good..

ugnhh

trevor

 

bad engine?

 

Poor compression wouldn't cause a miss at various RPMs.

 

Try throwing a timing light on both leading wires and see if you're getting spark or not at the miss.

 

sounds like it could be your TPS sensor, mine had that id start it and itdd miss like crazy and shake and **** but when it hit higher rpms it was ok and at idle itdd like pulse and stuff like rev up and down. anyway try taking the sensor off and spraying the moving part with wd40 and like shaking it to get any crap out thats in it. It worked for me. I hope this is of some help to you. good luck bro.

 

sounds like it could be your TPS sensor, mine had that id start it and itdd miss like crazy and shake and **** but when it hit higher rpms it was ok and at idle itdd like pulse and stuff like rev up and down. anyway try taking the sensor off and spraying the moving part with wd40 and like shaking it to get any crap out thats in it. It worked for me. I hope this is of some help to you. good luck bro.

 

I replaced the sensor so i doubt it is that.....

I'll check it though. The compressing is great so i know it's not blown......

trevor

 

air flow meter

 

OK update- i just replaced the CAS, the alternator, the trailing coils, the tps is fine, and retimed it. I am going out to change the mafs right now, then it's off tho autozone to checkon a cpu.......

 

Ok still nothing damnit........mafs wasn't it.... off to the ZONE!

 

Does it idle roughly/poorly? At what RPM does it idle? Almost every time i've had a hesitation it's been due to vac leaks

 

Have you checked all your grounds? Not just the engine one. I know I had some hesitations/missing at rpms, very slightly though not to the degree of you, and then I redid all my grounds in the grounding how-to plus a couple more and all my hesitations and everything went away. This is adding grounds to the coils, engine, replacing the negative battery terminal ground to the body and then to the block, ecu ground, boost sensor, uhm the one under the UIM, i can't remember them all. I have the how-to and pics (not very good ones but still gives you an idea) from the archives on my comp if you want it.

 

a vacuum leak on an NA wont cause the car to hesitate so severly that it won't run...you never mentioned if you checked the plugs - what if the electrode on one or more is completely gone. check the fuel pump for proper operation as well.

 

since when has autozone carried MAF's??????

 

he said he tried a MAF - I think he was going to autozone to see what they diagnose the car with

 

sounds like definatly fuel,.. check the pump? FPR? pressure? injectors?

 

Ok well, I put a timing light on the car and had my brother in law rev it up to the point where it started missing...I put the "clamp" on the leading coil and the light got to the point where it was flashing so fast it was solid, now when i put it on the trailing coil it would flash normal in the low rpms and disapear when it started missing (around 4.1k) Now these are new coils so i know the coils are good, i replaced the Crank angle sensor with one off a running car and that didn't help, the plugs have been inspected and are fine, I'm going to the junk yard tommorrow to find a cpu. Autozone doesn't carry them (suprised?). Any way i also replaced the bac valve and i am going to add a couple more grounds i guess. Thanks again but keep the sudjestions comming

here is the NEW list of things i've tried replacing.

Alternator
MAF
Coils (leading and trailing)
Crank angle sensor
Plugs
Wires
TPS
Fuel filters

It really seem to be electrical, if it were fuel the coil would't stop firing would it?

 

What about voltage regulator...what does that do? where is it ? could that be it? Crap!!!!

 

thats in the alternator so nix that...I still think it sounds like a fuel problem. maybe you have an injector stuck open...it dumps fuel and the car breaks up. ECU's very very rarely go bad.

 

u might have a short in ur elcetical system some where

 

doubtful that there could be such an electrical problem that would only effect engine operation. check the harness for exposed or grounded wires just in case...

 

I know you mentioned the sprak plugs are fine, but how old are they? I would strongly recommend changing them. I did taht in mine it it help some of the problems I was having. BTW are the spark plug wires showing any signs of arching? If they you migh need to replace those as well..

 

Hmm well this thread will give me something to think about while i fall asleep tonite. Seems like you've hit almost everything already, I'd say check the injectors just in case, but it really sounds ignition related to me

 

That's what i was thinking considering the fact that it isn't flooding and car will run and idle ok, so i don't think it's fuel pump.... but what else is there to the ignition system besides coils, plugs wires, cas? is the ecu even in the mix there? It's like i have a problem never incountered before........at least according to the search function anyways...which isn't working right now anyways........

 

I had a problem with my 7 at higher RPMs the sencondary injector somehow got unplugged from the harness