Stumble around 50mph.

I have a 95 formula and it stumbles if I let off the gas and hesitates(car speeds up but rpms don't move) when I try to accelerate when I hit 50 mph. If I keep the rpms above 2k it does fine it's just when I try to cruise. Any slower then 50mph and it doesn't do it. I know I need to hook it up to a scanner and blah blah blah. But at the moment I can't. I ordered the obd1 scanner with the obd2 conversion cable and it still won't read the computer. Any suggestions? I cleaned the the maf and replaced the fuel filter and nothing changed and the check engine light will come on after driving for a while but will go off.

First thing to check is fuel pressure and clean the MAF. After that, I would consider the EGR or a vacuum leak as the next most likely culprits. And, if it applies to your car, let's not forget the joys of a failing Optispark.

Thanks for the reply! I've cleaned the maf already and nothing changed. I gutted the cat cuz it was making a rattling noise( I thought it was plugged up) still didn't solve it. I believe I'll look into the egr next. Is there a quick test like disconnecting it to test it that's the culprit? I know I can take it off and use a hand pump the move the diaphragm on the valve but is there a test for the solenoid?

There is, but since our car does not have an EGR I cannot provide you with a diagnostic. On old school EGR valves you could see the diaphragm moving the rod when the engine was revved.

Ok so what code is it storing?


Take it to autozone and have them read the code.

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Originally Posted by 5.0THIS

Ok so what code is it storing?


Take it to autozone and have them read the code.

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U must not own the amazing 95 fbody.....autozone, O'Reillys, and advanced auto can't scan them. Obd2 plug with a obd1 computer is a bitch. As soon as my 16 pin to USB comes in I'll just hook it up and scan myself but till then just wondering if anyone had similar issues and know what the fix is.

I used to own a 95. Never had an issue pulling codes from it. Anyways... find out what the code is before you proceed. Otherwise you're throwing darts with a blindfold on. An OBD1 scanner with the correct adapter cable will scan your car. If you're going to keep the car, go get one, or get friendly with the dealer and see if they'll be nice about it and just pull the code for you (they might)

Whatever you do, don't go throwing parts at it and hoping for the best. You'll spend more money.

Quote:

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Originally Posted by 5.0THIS

I used to own a 95. Never had an issue pulling codes from it. Anyways... find out what the code is before you proceed. Otherwise you're throwing darts with a blindfold on. An OBD1 scanner with the correct adapter cable will scan your car. If you're going to keep the car, go get one, or get friendly with the dealer and see if they'll be nice about it and just pull the code for you (they might)

Whatever you do, don't go throwing parts at it and hoping for the best. You'll spend more money.

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To a certain extent throwing small parts at it I'm cool with. I'm not the type to ignore small parts of my car till they mess up and since the car is new to me I can only assume it's all original parts. Until I get the right scanner ordered I guess I'll just start with egr, plugs and wires. Hopefully that solves it. Thanks for the advice!