i have driven it quiet a bit now and i can tell more about what it is doing pulling out you can get on it pretty good and it will take off good you can run it onlevel road cruise at 40 or 5o mph runs good but just barely move gas pedal it starts to jerk or if you are cruising and it has tostart pulling a little bit it will buck and jump but you can mash the pedal on down and it will smoth back out again replaced map;plugs,wires,rotor,dist.cap coil.checked for vacum leak but can`t find onethanks

 

Okay, a couple of other questions.

If your truck has dual tanks does it behave the same way regardless of which tank you are running on? Also have you checked your fuel repulator and checked the IAC as well as clean the throttle body as suggested by one of the previous posts? Any of these areas could also cause the problem that you are describing.

If it does this but only on one tank as opposed to the other then start looking at that fuel pump and or the delivery lines.

 

it only has one tank i have cleaned the ica i pulled codes with koeo got a 172,327 and 328 need help with these thanks

 

172 - HEGO sensor circuit indicates system lean (right side)

327 - DPFE or EVP circuit below minimum voltage of 0.2 volts.

328 - EVP circuit below minimum voltage of 0.24 volts.


I am not an expert but all of these codes would lead me to check the EGR valve and the position sensor on top of it. I think what they tell me is that the EVP (EGR valve position sensor on top of the EGR valve) is not getting a proper reading either because the EGR is not working properly or the sensor is not. I would not worry about the HEGO (oxygen sensor) as it is a symptom of the EGR problem. It is running lean because to much air (or exhaust) is getting in.

Like I said I am not expert, just played around a lot with mine including rebuilding the engine. I did have a somewhat similar problem, but not as sever as your a few years ago and it was may EGR. It was the original and had become a little weak so at enough of an engine load the exhaust provided enough pressure to push it open a little before it should have been opening.

I would pull the EGR off and give it a good cleaning, use carb cleaner. Also ensure the ports are clear of carbon, not leaking around the gasket. If you pull it off you may want to pick up a new gasket first. Check the vacuum line that goes to the EGR and be certain that it is not leaking, melted closed, etc.

If your EGR is the same as mine on my 1992 5.8 it should just unbolt and then lift out, there is no need to undo the pipe at the bottom of the EGR as it slides out of a fitting on the other end but yours could be different. This is where a Haynes Catologue comes in handy. Have you got one?

Good luck, let me know what you find.

 

thank you ihave the throttle body off right now cleaning it cleaned the air valve tested tps got new gaskets will replace everything tomorrow and will clean egr valve iwill let you know how it turns out this thing will run fine crusing at 70 or 75 on interstate it never tryed to stall out and it cranks good every time i`m just puzzeld with it thanks again.

 

It seems like you have fixed a few of the original problems. How does it shift now from 1st to 2nd?

When you do the EGR cleaning make sure the ports into the intake are cleaned and that the point on the end of the EGR is nice and clean and seats well. You will see what I mean when you take it off. To see that it will mean removing the lenght of pipe. Be carefull as they can be really stuck on after several years. A work bench and vice will help a lot if you have one...or a couple of wrenches and a friend!

 

cleaned egr iac and put back still same thing checked fuel pressure it don`t snap up like it should it only comes up a few psi each time you switch on but after a few times it will come up to 38 to 40 can hear pump run a couple sec. each time supposed to have new pump i changed filter it only single tank could it be regulater or plugged line i also let it set for 6 hrs and it dropped to about 32 psi i don` t know where to start thanks.

 

truck is still missing fooling with it to day can start it up let it warm up misses alittle bit can pull connecter off no.8 injecter put back on and it will smooth out also it misses just above idle switch it off and restart it it starts missing again could this be injecter or wiring any help would be appr. thanks

 

still can` figure this thing out

 

I just fixed my miss with an injector cleaning/rebuild and intake reseal. Good luck. I have been playing with this truck for over a month. It was running rich and I could hear it popping through the intake until open loop. figured it was a lean condition. I couldn't find a vacuum leak but that is what it was acting like. bog off the line, bad miss at load, slight miss at idle, really poor cold acceleration. Hope this helps. v8's are notorious for cross firing so check your spark plug wire routing. spray some soapy water at the wires in the dark. you can see where and if the wires are arcing off anything.

 

thank you i am plannin o getting injecters i have tryed 3 or 4 times today start it up it misses pull no. 8 injecter wire plug back up runs good drive it don`t jerk or buck switgh it off and re start same miss again only code is 172