chicofuentes0224 Posted November 6, 2007 Share Posted November 6, 2007 oh where to start. I bought this comanche in june and am tryin to nurse it back to health. It seems to have a hundred problems but let's start with this one. I changed the ccv tubing coming out of the valve cover to try and slow that oil leak into the air box. It worked. Sort of. Thetruck was running good for a little and then after it warmed up it would have trouble at about 2000 rpm and 35 mph(stuttering) shifting. oh I forgot to tell you. It's 1988 4.0 A/T. Well after reading 643 posts I decided to start by changing the TPS. I had a friend who is a professional vw mechanic come and bring his little thousand dollar machine to check the volts coming out and going in of the TPS. He set it to the spec you guys wrote in some posts on the furum. Well I drove it for about 20 miles and it worked great. I thought the problem was solved. Then it started stuttering again. Kinda like it wasn't getting enough fuel. After rereading 643 posts I decided to change th O2 sensor. That was rusted and black as in burnt so I suppose it was the original. Drove it again but I'm still having the same problem. So I call my buddy and he says check the fuel pressure. What do i DO THIS WITH. On a whim I decide to open the hood up again and I notice that the grommet on the back of the valve cover is once again leaking oil. I disconnect the line at the grommet, let it hang over the valve cover and took it for for a drive. The truck seems to run a lot better. It almost shifts where it's supposed to and doesn't seem to stutter at all. So now i figure that this is an air problem. Now Here's my questions. 1) What should I look for next? 2) Should I try and get the valve cover off and clean underneath to try and solve this problem so air actually gets to the intake instead of oil. 3)would it hurt anything if I just plugged the hole on the back of the valve cover and put some kind of breather or filter on the small valve going in to the intake? 4) Should I go ahead and change the fuel pump? and what else should I change with the fuel system since I'm basically now starting to rebuild the whole truck. Thanks for any help you guys can give me. Link to comment Share on other sites More sharing options...
Eagle Posted November 7, 2007 Share Posted November 7, 2007 Removing the valve cover and cleaning it up would be a good idea. There is a baffle inside there that can get clogged. Can't hurt. Before you change the fuel pump, have you replaced the fuel filter? It's mounted on the driver's side frame rail, sort of near the back of the cab. Most owners don't know it should be changed regularly. Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 I haven't personally changed it yet,but right before I bought it, it looked like a tune up was done including the fuel filter. I just ran the truck without that hose connected to the valve cover and it's still stuttering around 2000 rpm's and 35 mph. I had my buddy check the tps again and it's on spec. I guess I'm going to get the fuel pressure checked tommorow and maybe change that map sensor. Link to comment Share on other sites More sharing options...
ejndssn Posted November 7, 2007 Share Posted November 7, 2007 would the EGR cause this same type symptom. and would this be an item to check just a thought :popcorn: Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 ok i know where the egr is . how do i check it. Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 Never mind. Found the post :D Link to comment Share on other sites More sharing options...
Eagle Posted November 7, 2007 Share Posted November 7, 2007 I haven't personally changed it yet,but right before I bought it, it looked like a tune up was done including the fuel filter. It "looked like" a tune up was done? Including the fuel filter? Are you saying you crawled under the vehicle and saw a new fuel filter canister bolted to the frame rail? Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 Yes sir I think so. Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 Well it's gotten worse. It's stuttering at anything over 20 mph Link to comment Share on other sites More sharing options...
pingpong Posted November 7, 2007 Share Posted November 7, 2007 Sounds like a bad fuel pump Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 Yeah nI'm going to check the pressure now. Let you know what happens then. Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 7, 2007 Author Share Posted November 7, 2007 fuel pressure is good at the rail. I'm gonna change the plugs and the fuel filter now. Link to comment Share on other sites More sharing options...
feerocknok Posted November 7, 2007 Share Posted November 7, 2007 Do a full tune up! Plugs, wires, cap, rotor, air filter, oil filter, fuel filter. Costs under $100 and your truck will be happier, even if it only needed one of those things to run. Link to comment Share on other sites More sharing options...
FxRacing282 Posted November 8, 2007 Share Posted November 8, 2007 fuel pressure is good at the rail. I'm gonna change the plugs and the fuel filter now. sounds like an air or fuel issue. what did you do with the EGR valve? Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 8, 2007 Author Share Posted November 8, 2007 Nothing yet. I'm gonna change the plugs first and the fuel filter tosee if that fixes it. If not I'll keep searching. Maybe the map or egr next? Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 8, 2007 Author Share Posted November 8, 2007 Well, changed the plugs(ngk's) wires, cap and rotor. And yes eagle, I changed the fuel filter today and the crap coming out of it was dirty. The cap looked shot inside. You couldn't tell it was brass anymore. The plugs were all covered in black soot except number 4. It was white. Do you think the injector is running lean or sticking? Anyway the truck runs a bit better but it did not solve the problem. I'm still feeling a shudder after 2000 rpm. My mechanic friend said ask you guys if you think the CPS could be causing this problem. That's my next guess. Or do you think I should change the MAP sensor or EGR next? Everybody please chime in with a guess :D Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 21, 2007 Author Share Posted November 21, 2007 Help me!!! I can not for the life of me get this truck to run right. I'm still having this problem where the truck stutters at 2000 rpm until it shifts. We replaced the TPS and tried adjusting it. The output is 4.2 volts but we can't get the input at 5 volts. Do yinz think we need to try a different TPS because this one might be faulty? Link to comment Share on other sites More sharing options...
dakal Posted November 22, 2007 Share Posted November 22, 2007 buy the tps at the dealer. the wires are bett :D er and it solved my problem Link to comment Share on other sites More sharing options...
chicofuentes0224 Posted November 22, 2007 Author Share Posted November 22, 2007 Which problem did it solve Link to comment Share on other sites More sharing options...
dakal Posted November 22, 2007 Share Posted November 22, 2007 i was hunting jerkiness on accelation? should of paid attention to spelling and not the girls. not! i couldn't get to the low or high adjustments with the tps. was told the dealer parts were better. i had bought a aftermarket tps, so i compared it to the dealer one. the wires were a much better grade. as i have said before on this forum, will only buy sensors from the dealer. buy the way, i paid $14.00 less from the dealer. i have replaced all the sensors now. i have one stumble on hard accelation, sometimes. still looking for cause. 8) Link to comment Share on other sites More sharing options...
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