Hi, ajnolin! Thanks for your reply. Yes, we verified that there was a good fuel supply; holding down the pin on the valve and cranking the engine produced a good amount of fuel (quite a lot actually), although I don't have a fuel pressure gauge to measure it. If I get a hold of one, what should the correct pressure reading be? Thanks again for your reply!

 

Hi, Everyone! Well, I'm back to report on what I did and the current situation. Since last time, I've checked the continuity of the TPS and it seems to be OK, so I reinstalled/reconnected it. I've changed the spark plugs (new), checked the wires for arching (none found), checked the contact points of the plug wires and Distributor cap inside and out (cleaned up & all OK), checked for obvious vacuum hose leaks (none found), and there are no apparent signs of grounding from any bare wires. I've put in more fresh gasoline (3/4 tank with fuel injector cleaner/dry gas additive). Currently, there are no codes showing on the OBD box (verified it was working and had a 17 displayed, but when I reconnected the TPS and cleared the fault it went away and has not reappeared), and there are no warning lights of any type showing (although I guess that doesn't rule out them being burned out - for example, since I don't see the ABS light on anymore - it used to stay on until you reached a slow speed- or the little green trailer light when you started/used your blinker - I'm assuming they burnt out).


OK... so right now, the operating condition is as follows: it starts up, and in Park (or any gear, standing still) idles beautifully at about 750 rpms, and (in Park or Neutral) you can step on the gas and it goes great, without a ping, knock or miss! However, when it's time to drive, you step on the gas and it gags, knocks, misfires and runs like crap, with literally no acceleration ability immediately, and needs a quarter-mile run to get to 35mph. Even at that running speed, if you were to floor it, it gags, backfires and feels like it's going to cut out. Any ideas? Please Help! Thanks again for your interest and input!

 

Check vacuum advance and mechanical weights. Vacuum advance for perforated diaphragm and mechanical for corrosion, spring condition and weight movement.

 

Hi, ihscouts! Thank you (again) for your reply and input. I will look up your suggestions in the workshop manual, find out what/where they are (LOL) and report back! I really appreciate the input!

 

Hello Everyone - Well, here's the update...after determining that the vacuum advance was the most likely culprit, we purchased and installed a brand new one...but no improvement. There doesn't seem to be enough vacuum to operate the vacuum advance on the distributor. We checked all of the vacuum hoses for leaks (by visual inspection, as well as using carb cleaner sprayed over the hoses, looking for an increased idle response) and blockage, but found nothing. Additionally, we checked the vacuum line that runs from the plenum to the brake bellows (vacuum assisted brakes) and found no leaks; there is plenty of vacuum in that hose. Any other ideas/insights? I'm starting to think that perhaps the TPS is not working after all, and that might be my next step on the replacement trail, although it is expensive. As always, your thoughts/insight is very much appreciated. Thanks again!

 

Yes - lack of fuel! I had this exact scenario before and ended up the fuel pump wasn't putting out enough fuel to keep up with the demand of the engine under a load. Do like someone else said and grab a gauge and observe the pressures while the system is running. Don't forget about the fuel pressure regulator as a component of the system. I'm not sure about this vehicle but I know some that have vacuum lines attached to the regulator.

'Backfires' (out of the tailpipe) are caused by overly rich fuel mixtures. 'Front Fires' (a popping sound in the intake, usually coupled with momentary hesitation) are caused by too lean of a fuel mixture; ie. not getting enough fuel. From your description above, it sounds like you may be getting a front fire.

If we're right, you owe us both a beer!

 

Thanks for your reply and suggestion, june82000! Do you/does anyone happen to know what the correct fuel pressure should be? I thought I read somewhere that it should be at a minimum of 31/psi, but I'm not sure if I am recollecting correctly, and I'm NOT a mechanic (rather, an eager Do-It-Yourself-er...with a Father-in Law who's not always right...but he's just never wrong...LOL!!!...just kidding, he's Great!). Ahem,...anyways, as always, I appreciate the replies and insight! Thanks again!

 

Hello Everyone....OK, update: I found out what the correct fuel pump delivery pressure should be. Question: Can anyone suggest a good fuel pump pressure gauge? As always, Thanks!

 

Go to your local auto parts store, more than likely you can rent one for free. Harbor freight tools has a pretty cheap also. Once you hook it up you can see what the pressure is it idle then press on the gas and see if it drops off a lot.

 

Hello, Everyone! Good News! Yes, it was in fact the fuel pump! Changed it out, and it solved the problem. Kudos to you all for your help with that issue!! Now that it's running great, it's time to move on to the next immediate issue...how to make it stop great!!


I'm questioning the brakes in general, and I'm not sure that the ABS System is working any longer. There is no "pulsing" felt through the brake pedal when applying the brakes any longer at any point of braking; the braking system doesn't seem to engage sharply, and the distance to stop is too long. We checked the pads, rotors, caliper pistons and fluid level, and all are OK. There is no noise coming from the brakes when applied, and there are no obvious signs of leakage. There are no warning lights on (but, as an aside, the ABS indicator light hasn't lit up in years - probably burned out...checking that issue).There is good vacuum up to the brake bellows, but we're not sure if the power assist bellows are working. Any ideas on how we can check to see if the vacuum power assist is working correctly? As always, your ideas/insight is greatly appreciated! Thanks again!