Hello all. I am new to th forum, and I must admit upfront, I am no mechanic in the least. Here is my question. I have a 89' F150, 8cyl-302, 5-spd. I have not done much work since purchasing it (I paid way too much for it though). I had the egr senor replaced and some other work done to pass inspection. My problem is that when I press on the accelerator, the engine idle is delayed. For example, when I press the accelerator down and release it, the engine doesn't rev up until the release. In addition also, when the truck has been driven for a few miles and I kill the engine, say to get gas or someething, it struggles to retart. I haven't had te battery tested or replaced since te purchase, but it seems to be something else. Any suggestions.

 

First, welcome to the site! Always glad to see the owners of the 'older' model years come on-board. We've learned lots of stuff here, now if we could only remember it :-)

Now, all seriousness aside, on to the problem at hand. Always have to ask if the computer codes have been pulled - has your 'check engine' light come on while running?

Just a WAG - but at this point, thinking about the Throttle Position Sensor (TPS). Another thought is insufficient fuel flow - restricted fuel filter or poor pump performance.

When you mention 'struggles to restart' - is this the engine fighting to turn over, or is it turning over normally but not lighting off?

Suggest to consider getting any codes pulled first before blindly replacing parts.

 

Thanks for the welcome and reply. To answer the question about the codes, before I got the truck inspected, I had a diagnostic ran to see what, if any codes would come up and hinder the truck from passing inspection. It called for the EGR valve and a power stearing sensor (or something like that). That was taken cared of and a few other tweaks were made to pass inspection. As of lately, I don't think that any codes are showing otherwise it wouldn't have passed. You mentioned the TPS, what exactly is that? Also, the struggle to turn over is a "fight" to turn over, kinda like the engine is fatigued. If I let it rest for a while, it will kick over with no problem. Now I admit that I will have a tune up done to it soon, but I need to know if there would be anything that I need to worry about. Also, I do plan on putting another engine and tranny in there.

 

It is my understanding that one of the Throttle Position Sensor (TPS) functions is to serve as an anticipator - the computer monitors changes in this sensor to get a jump on fuel flow changes and perhaps timing changes that need to be made.

Going way beyond my confidence level of understanding - but just got to wondering that if this TPS signal were faulty, then everything that relies on it will be in error also. The computer should have caught this and flagged it as a fault with the 'check engine' lamp and a code stored in memory.

As for the 'turning over' issue - some suggestions could be a weak battery, poor connections, faulty wiring (have seen corrosion up under the insulation), burnt contacts on the relay, or a tired starter. At this point from what you describe, not thinking it is with the ignition or fuel system - unless the base timing has somehow changed.

 

The TPS gasket will be the culprit to the delayed idle. I had to replace mine with a special gasket that changed the the coordination of the acceleration and idle. Unfortunately I don't remember where I got it from. I haven't done anything in that realm for almost 15yrs and haven't changed it since. As far as the "fatigue" of the engine, I would look at the starter. Mine is actually doing the same thing. I am looking at the starter...