Hi There,

It seems there has been a few cases like this one, but I have found no definitive solution. I have a 92' that randomly hesitates or 'fishbites' every few days. It goes from a slight hitch, to sometimes to a terrible shake like I cannot drive a stick. I can drive it for a week sometimes without trouble. I get a code 27 and even had a mechanic scan it (took a while to find one with obd1 scanner). Fuel injector drivers were randomly 'not responding'. I replaced all 6 injectors and the PCM. I also have replaced coil, distributor cap and rotor, plugs and wires. I had a fuel system "treatment" done by the mechanic where he pressurized the fuel rail and injected cleaner. But I am still having this problem. The mechanic said he bypassed the fuel filter, so that should not be an issue, and assured me the fuel pump was fine.

Any suggestions?

Thanks in advance =)

 

my 89 was acting like this a while back chec the cps wire mine had rubbed and was touching the motor every so often causing it to act up

 

Thanks for the tip! I'll check this asap...

 

Hi There, I thought I would update this as I have made some progress on the check engine light. I had a pretty good oil leak - the oil pan, rear main, and oil filter adapter were all leaking. I was trying to resolve the check engine light before I fixed these, but it seems this was the root of my problem. I assume the oil was interfering with the CPS readings as I have not had any check engine light since fixing the leaks. I am however still getting some hesitation, so maybe the CPS is also bad or I need to pull it out and clean it.

On another problem, when driving at cruising speed I sometimes get a loud almost grinding noise. The best I can describe it is when you grind gears, but not quite the same. When this happens my speedometer drops, though no loss in speed or noticeable power. It only happens for an instant then all is normal again. Any ideas on this?

 

Unless already done, I'd get that fuel filter back in-line. It is necessary.............

 

yeah filter was put back after the diagnostic.

I have found if I pulsate the gas pedal while cruising the grinding sound will start. Could it be a mount? Almost sounds like something hits the flywheel. While trying this I got my check engine light back too. Bout ready to drive it in a lake.

 

Check the torque converter bolts. I've read on here or another forum of them coming lose. This could explain both issues. Are you sure its fuel related?

 

AW4 or manual? I have the aw4 and my tranny would jerk once in awhile, kinda like what you described. It would do it or a while then stop. Then it kept doing it, took it to a mechanic, he couldn't find anything. He took it to 6 other mechanics with the same result. After all that driving, it started working normally again. So he returned it and only charged me for he mechanic shop visits. ( which I was very thankful for). My FIL and I decided to trace it out. Found out that one of the fuses to the tranny would only make contact on one of the sides. The metal piece that you press the fuse into somehow worked a gap into them. We bent those in a bit and haven't had and issue since. Not saying this is the issue, just a possibility Good luck and keep us posted.

 

Hi, figured I would update this as the code 27 problem seems to be fixed. After 3 mechanics and my own toiling, I found wires inside the wiring harness that runs along the firewall to be melted. I replaced this section of the harness and all seems to be well after several months of daily driving. Thanks to all for your help!

P.S.
The "grinding" noise is still here and there. Not sure what it is, most times my speedometer gives out when it occurs. My mechanic told be to just run it till it dies, then replace the transmission.